cc: Chromify RenderSurfaceFilters.

cc/render_surface_filters.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/render_surface_filters.h"
 
 #include "base/logging.h"
 #include "skia/ext/refptr.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebFilterOperation.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebFilterOperations.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/effects/SkBlurImageFilter.h"
 #include "third_party/skia/include/effects/SkColorMatrixFilter.h"
 #include "third_party/skia/include/effects/SkMagnifierImageFilter.h"
 #include "third_party/skia/include/gpu/SkGpuDevice.h"
 #include "third_party/skia/include/gpu/SkGrPixelRef.h"
 #include "ui/gfx/size_f.h"
 
 namespace cc {
 
 namespace {
 
-void getBrightnessMatrix(float amount, SkScalar matrix[20])
-{
-    // Spec implementation
-    // (http://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#brightnessEquivalent)
-    // <feFunc[R|G|B] type="linear" slope="[amount]">
-    memset(matrix, 0, 20 * sizeof(SkScalar));
-    matrix[0] = matrix[6] = matrix[12] = amount;
-    matrix[18] = 1;
+void GetBrightnessMatrix(float amount, SkScalar matrix[20]) {
+  // Spec implementation
+  // (http://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#brightnessEquivalent)
+  // <feFunc[R|G|B] type="linear" slope="[amount]">
+  memset(matrix, 0, 20 * sizeof(SkScalar));
+  matrix[0] = matrix[6] = matrix[12] = amount;
+  matrix[18] = 1.f;
 }
 
-void getSaturatingBrightnessMatrix(float amount, SkScalar matrix[20])
-{
-    // Legacy implementation used by internal clients.
-    // <feFunc[R|G|B] type="linear" intercept="[amount]"/>
-    memset(matrix, 0, 20 * sizeof(SkScalar));
-    matrix[0] = matrix[6] = matrix[12] = matrix[18] = 1;
-    matrix[4] = matrix[9] = matrix[14] = amount * 255;
+void GetSaturatingBrightnessMatrix(float amount, SkScalar matrix[20]) {
+  // Legacy implementation used by internal clients.
+  // <feFunc[R|G|B] type="linear" intercept="[amount]"/>
+  memset(matrix, 0, 20 * sizeof(SkScalar));
+  matrix[0] = matrix[6] = matrix[12] = matrix[18] = 1.f;
+  matrix[4] = matrix[9] = matrix[14] = amount * 255.f;
 }
 
-void getContrastMatrix(float amount, SkScalar matrix[20])
-{
-    memset(matrix, 0, 20 * sizeof(SkScalar));
-    matrix[0] = matrix[6] = matrix[12] = amount;
-    matrix[4] = matrix[9] = matrix[14] = (-0.5f * amount + 0.5f) * 255;
-    matrix[18] = 1;
+void GetContrastMatrix(float amount, SkScalar matrix[20]) {
+  memset(matrix, 0, 20 * sizeof(SkScalar));
+  matrix[0] = matrix[6] = matrix[12] = amount;
+  matrix[4] = matrix[9] = matrix[14] = (-0.5f * amount + 0.5f) * 255.f;
+  matrix[18] = 1.f;
 }
 
-void getSaturateMatrix(float amount, SkScalar matrix[20])
-{
-    // Note, these values are computed to ensure matrixNeedsClamping is false
-    // for amount in [0..1]
-    matrix[0] = 0.213f + 0.787f * amount;
-    matrix[1] = 0.715f - 0.715f * amount;
-    matrix[2] = 1.f - (matrix[0] + matrix[1]);
-    matrix[3] = matrix[4] = 0;
-    matrix[5] = 0.213f - 0.213f * amount;
-    matrix[6] = 0.715f + 0.285f * amount;
-    matrix[7] = 1.f - (matrix[5] + matrix[6]);
-    matrix[8] = matrix[9] = 0;
-    matrix[10] = 0.213f - 0.213f * amount;
-    matrix[11] = 0.715f - 0.715f * amount;
-    matrix[12] = 1.f - (matrix[10] + matrix[11]);
-    matrix[13] = matrix[14] = 0;
-    matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0;
-    matrix[18] = 1;
+void GetSaturateMatrix(float amount, SkScalar matrix[20]) {
+  // Note, these values are computed to ensure matrixNeedsClamping is false
+  // for amount in [0..1]
+  matrix[0] = 0.213f + 0.787f * amount;
+  matrix[1] = 0.715f - 0.715f * amount;
+  matrix[2] = 1.f - (matrix[0] + matrix[1]);
+  matrix[3] = matrix[4] = 0.f;
+  matrix[5] = 0.213f - 0.213f * amount;
+  matrix[6] = 0.715f + 0.285f * amount;
+  matrix[7] = 1.f - (matrix[5] + matrix[6]);
+  matrix[8] = matrix[9] = 0.f;
+  matrix[10] = 0.213f - 0.213f * amount;
+  matrix[11] = 0.715f - 0.715f * amount;
+  matrix[12] = 1.f - (matrix[10] + matrix[11]);
+  matrix[13] = matrix[14] = 0.f;
+  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
+  matrix[18] = 1.f;
 }
 
-void getHueRotateMatrix(float hue, SkScalar matrix[20])
-{
-    const float kPi = 3.1415926535897932384626433832795f;
+void GetHueRotateMatrix(float hue, SkScalar matrix[20]) {
+  const float kPi = 3.1415926535897932384626433832795f;
 
-    float cosHue = cosf(hue * kPi / 180);
-    float sinHue = sinf(hue * kPi / 180);
-    matrix[0] = 0.213f + cosHue * 0.787f - sinHue * 0.213f;
-    matrix[1] = 0.715f - cosHue * 0.715f - sinHue * 0.715f;
-    matrix[2] = 0.072f - cosHue * 0.072f + sinHue * 0.928f;
-    matrix[3] = matrix[4] = 0;
-    matrix[5] = 0.213f - cosHue * 0.213f + sinHue * 0.143f;
-    matrix[6] = 0.715f + cosHue * 0.285f + sinHue * 0.140f;
-    matrix[7] = 0.072f - cosHue * 0.072f - sinHue * 0.283f;
-    matrix[8] = matrix[9] = 0;
-    matrix[10] = 0.213f - cosHue * 0.213f - sinHue * 0.787f;
-    matrix[11] = 0.715f - cosHue * 0.715f + sinHue * 0.715f;
-    matrix[12] = 0.072f + cosHue * 0.928f + sinHue * 0.072f;
-    matrix[13] = matrix[14] = 0;
-    matrix[15] = matrix[16] = matrix[17] = 0;
-    matrix[18] = 1;
-    matrix[19] = 0;
+  float cos_hue = cosf(hue * kPi / 180.f);
+  float sin_hue = sinf(hue * kPi / 180.f);
+  matrix[0] = 0.213f + cos_hue * 0.787f - sin_hue * 0.213f;
+  matrix[1] = 0.715f - cos_hue * 0.715f - sin_hue * 0.715f;
+  matrix[2] = 0.072f - cos_hue * 0.072f + sin_hue * 0.928f;
+  matrix[3] = matrix[4] = 0.f;
+  matrix[5] = 0.213f - cos_hue * 0.213f + sin_hue * 0.143f;
+  matrix[6] = 0.715f + cos_hue * 0.285f + sin_hue * 0.140f;
+  matrix[7] = 0.072f - cos_hue * 0.072f - sin_hue * 0.283f;
+  matrix[8] = matrix[9] = 0.f;
+  matrix[10] = 0.213f - cos_hue * 0.213f - sin_hue * 0.787f;
+  matrix[11] = 0.715f - cos_hue * 0.715f + sin_hue * 0.715f;
+  matrix[12] = 0.072f + cos_hue * 0.928f + sin_hue * 0.072f;
+  matrix[13] = matrix[14] = 0.f;
+  matrix[15] = matrix[16] = matrix[17] = 0.f;
+  matrix[18] = 1.f;
+  matrix[19] = 0.f;
 }
 
-void getInvertMatrix(float amount, SkScalar matrix[20])
-{
-    memset(matrix, 0, 20 * sizeof(SkScalar));
-    matrix[0] = matrix[6] = matrix[12] = 1 - 2 * amount;
-    matrix[4] = matrix[9] = matrix[14] = amount * 255;
-    matrix[18] = 1;
+void GetInvertMatrix(float amount, SkScalar matrix[20]) {
+  memset(matrix, 0, 20 * sizeof(SkScalar));
+  matrix[0] = matrix[6] = matrix[12] = 1.f - 2.f * amount;
+  matrix[4] = matrix[9] = matrix[14] = amount * 255.f;
+  matrix[18] = 1.f;
 }
 
-void getOpacityMatrix(float amount, SkScalar matrix[20])
-{
-    memset(matrix, 0, 20 * sizeof(SkScalar));
-    matrix[0] = matrix[6] = matrix[12] = 1;
-    matrix[18] = amount;
+void GetOpacityMatrix(float amount, SkScalar matrix[20]) {
+  memset(matrix, 0, 20 * sizeof(SkScalar));
+  matrix[0] = matrix[6] = matrix[12] = 1.f;
+  matrix[18] = amount;
 }
 
-void getGrayscaleMatrix(float amount, SkScalar matrix[20])
-{
-    // Note, these values are computed to ensure matrixNeedsClamping is false
-    // for amount in [0..1]
-    matrix[0] = 0.2126f + 0.7874f * amount;
-    matrix[1] = 0.7152f - 0.7152f * amount;
-    matrix[2] = 1.f - (matrix[0] + matrix[1]);
-    matrix[3] = matrix[4] = 0;
+void GetGrayscaleMatrix(float amount, SkScalar matrix[20]) {
+  // Note, these values are computed to ensure matrixNeedsClamping is false
+  // for amount in [0..1]
+  matrix[0] = 0.2126f + 0.7874f * amount;
+  matrix[1] = 0.7152f - 0.7152f * amount;
+  matrix[2] = 1.f - (matrix[0] + matrix[1]);
+  matrix[3] = matrix[4] = 0.f;
 
-    matrix[5] = 0.2126f - 0.2126f * amount;
-    matrix[6] = 0.7152f + 0.2848f * amount;
-    matrix[7] = 1.f - (matrix[5] + matrix[6]);
-    matrix[8] = matrix[9] = 0;
+  matrix[5] = 0.2126f - 0.2126f * amount;
+  matrix[6] = 0.7152f + 0.2848f * amount;
+  matrix[7] = 1.f - (matrix[5] + matrix[6]);
+  matrix[8] = matrix[9] = 0.f;
 
-    matrix[10] = 0.2126f - 0.2126f * amount;
-    matrix[11] = 0.7152f - 0.7152f * amount;
-    matrix[12] = 1.f - (matrix[10] + matrix[11]);
-    matrix[13] = matrix[14] = 0;
+  matrix[10] = 0.2126f - 0.2126f * amount;
+  matrix[11] = 0.7152f - 0.7152f * amount;
+  matrix[12] = 1.f - (matrix[10] + matrix[11]);
+  matrix[13] = matrix[14] = 0.f;
 
-    matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0;
-    matrix[18] = 1;
+  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
+  matrix[18] = 1.f;
 }
 
-void getSepiaMatrix(float amount, SkScalar matrix[20])
-{
-    matrix[0] = 0.393f + 0.607f * amount;
-    matrix[1] = 0.769f - 0.769f * amount;
-    matrix[2] = 0.189f - 0.189f * amount;
-    matrix[3] = matrix[4] = 0;
+void GetSepiaMatrix(float amount, SkScalar matrix[20]) {
+  matrix[0] = 0.393f + 0.607f * amount;
+  matrix[1] = 0.769f - 0.769f * amount;
+  matrix[2] = 0.189f - 0.189f * amount;
+  matrix[3] = matrix[4] = 0.f;
 
-    matrix[5] = 0.349f - 0.349f * amount;
-    matrix[6] = 0.686f + 0.314f * amount;
-    matrix[7] = 0.168f - 0.168f * amount;
-    matrix[8] = matrix[9] = 0;
+  matrix[5] = 0.349f - 0.349f * amount;
+  matrix[6] = 0.686f + 0.314f * amount;
+  matrix[7] = 0.168f - 0.168f * amount;
+  matrix[8] = matrix[9] = 0.f;
 
-    matrix[10] = 0.272f - 0.272f * amount;
-    matrix[11] = 0.534f - 0.534f * amount;
-    matrix[12] = 0.131f + 0.869f * amount;
-    matrix[13] = matrix[14] = 0;
+  matrix[10] = 0.272f - 0.272f * amount;
+  matrix[11] = 0.534f - 0.534f * amount;
+  matrix[12] = 0.131f + 0.869f * amount;
+  matrix[13] = matrix[14] = 0.f;
 
-    matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0;
-    matrix[18] = 1;
+  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
+  matrix[18] = 1.f;
 }
 
 // The 5x4 matrix is really a "compressed" version of a 5x5 matrix that'd have
 // (0 0 0 0 1) as a last row, and that would be applied to a 5-vector extended
 // from the 4-vector color with a 1.
-void multColorMatrix(SkScalar a[20], SkScalar b[20], SkScalar out[20])
-{
-    for (int j = 0; j < 4; ++j) {
-        for (int i = 0; i < 5; ++i) {
-            out[i+j*5] = i == 4 ? a[4+j*5] : 0;
-            for (int k = 0; k < 4; ++k)
-                out[i+j*5] += a[k+j*5] * b[i+k*5];
-        }
+void MultColorMatrix(SkScalar a[20], SkScalar b[20], SkScalar out[20]) {
+  for (int j = 0; j < 4; ++j) {
+    for (int i = 0; i < 5; ++i) {
+      out[i+j*5] = i == 4 ? a[4+j*5] : 0.f;
+      for (int k = 0; k < 4; ++k)
+        out[i+j*5] += a[k+j*5] * b[i+k*5];
     }
+  }
 }
 
 // To detect if we need to apply clamping after applying a matrix, we check if
 // any output component might go outside of [0, 255] for any combination of
 // input components in [0..255].
 // Each output component is an affine transformation of the input component, so
 // the minimum and maximum values are for any combination of minimum or maximum
 // values of input components (i.e. 0 or 255).
 // E.g. if R' = x*R + y*G + z*B + w*A + t
 // Then the maximum value will be for R=255 if x>0 or R=0 if x<0, and the
 // minimum value will be for R=0 if x>0 or R=255 if x<0.
 // Same goes for all components.
-bool componentNeedsClamping(SkScalar row[5])
-{
-    SkScalar maxValue = row[4] / 255;
-    SkScalar minValue = row[4] / 255;
-    for (int i = 0; i < 4; ++i) {
-        if (row[i] > 0)
-            maxValue += row[i];
-        else
-            minValue += row[i];
-    }
-    return (maxValue > 1) || (minValue < 0);
-}
-
-bool matrixNeedsClamping(SkScalar matrix[20])
-{
-    return componentNeedsClamping(matrix)
-        || componentNeedsClamping(matrix+5)
-        || componentNeedsClamping(matrix+10)
-        || componentNeedsClamping(matrix+15);
-}
-
-bool getColorMatrix(const WebKit::WebFilterOperation& op, SkScalar matrix[20])
-{
+bool ComponentNeedsClamping(SkScalar row[5]) {
+  SkScalar max_value = row[4] / 255.f;
+  SkScalar min_value = row[4] / 255.f;
+  for (int i = 0; i < 4; ++i) {
+    if (row[i] > 0)
+      max_value += row[i];
+    else
+      min_value += row[i];
+  }
+  return (max_value > 1.f) || (min_value < 0.f);
+}
+
+bool MatrixNeedsClamping(SkScalar matrix[20]) {
+  return ComponentNeedsClamping(matrix)
+      || ComponentNeedsClamping(matrix+5)
+      || ComponentNeedsClamping(matrix+10)
+      || ComponentNeedsClamping(matrix+15);
+}
+
+bool GetColorMatrix(const WebKit::WebFilterOperation& op, SkScalar matrix[20]) {
+  switch (op.type()) {
+    case WebKit::WebFilterOperation::FilterTypeBrightness: {
+      GetBrightnessMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness: {
+      GetSaturatingBrightnessMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeContrast: {
+      GetContrastMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeGrayscale: {
+      GetGrayscaleMatrix(1.f - op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeSepia: {
+      GetSepiaMatrix(1.f - op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeSaturate: {
+      GetSaturateMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeHueRotate: {
+      GetHueRotateMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeInvert: {
+      GetInvertMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeOpacity: {
+      GetOpacityMatrix(op.amount(), matrix);
+      return true;
+    }
+    case WebKit::WebFilterOperation::FilterTypeColorMatrix: {
+      memcpy(matrix, op.matrix(), sizeof(SkScalar[20]));
+      return true;
+    }
+    default:
+      return false;
+  }
+}
+
+class FilterBufferState {
+ public:
+  FilterBufferState(GrContext* gr_context,
+                    gfx::SizeF size,
+                    unsigned texture_id)
+      : gr_context_(gr_context),
+        current_texture_(0) {
+    // Wrap the source texture in a Ganesh platform texture.
+    GrBackendTextureDesc backend_texture_description;
+    backend_texture_description.fWidth = size.width();
+    backend_texture_description.fHeight = size.height();
+    backend_texture_description.fConfig = kSkia8888_GrPixelConfig;
+    backend_texture_description.fTextureHandle = texture_id;
+    skia::RefPtr<GrTexture> texture = skia::AdoptRef(
+        gr_context->wrapBackendTexture(backend_texture_description));
+    // Place the platform texture inside an SkBitmap.
+    source_.setConfig(SkBitmap::kARGB_8888_Config, size.width(), size.height());
+    skia::RefPtr<SkGrPixelRef> pixel_ref =
+        skia::AdoptRef(new SkGrPixelRef(texture.get()));
+    source_.setPixelRef(pixel_ref.get());
+  }
+
+  ~FilterBufferState() {}
+
+  bool Init(int filter_count) {
+    int scratch_count = std::min(2, filter_count);
+    GrTextureDesc desc;
+    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
+    desc.fSampleCnt = 0;
+    desc.fWidth = source_.width();
+    desc.fHeight = source_.height();
+    desc.fConfig = kSkia8888_GrPixelConfig;
+    for (int i = 0; i < scratch_count; ++i) {
+      GrAutoScratchTexture scratch_texture(
+          gr_context_, desc, GrContext::kExact_ScratchTexMatch);
+      scratch_textures_[i] = skia::AdoptRef(scratch_texture.detach());
+      if (!scratch_textures_[i])
+        return false;
+    }
+    return true;
+  }
+
+  SkCanvas* Canvas() {
+    if (!canvas_.get())
+      CreateCanvas();
+    return canvas_.get();
+  }
+
+  const SkBitmap& Source() { return source_; }
+
+  void Swap() {
+    canvas_->flush();
+    canvas_.clear();
+    device_.clear();
+
+    skia::RefPtr<SkGrPixelRef> pixel_ref = skia::AdoptRef(
+        new SkGrPixelRef(scratch_textures_[current_texture_].get()));
+    source_.setPixelRef(pixel_ref.get());
+    current_texture_ = 1 - current_texture_;
+  }
+
+ private:
+  void CreateCanvas() {
+    DCHECK(scratch_textures_[current_texture_].get());
+    device_ = skia::AdoptRef(new SkGpuDevice(
+        gr_context_, scratch_textures_[current_texture_].get()));
+    canvas_ = skia::AdoptRef(new SkCanvas(device_.get()));
+    canvas_->clear(0x0);
+  }
+
+  GrContext* gr_context_;
+  SkBitmap source_;
+  skia::RefPtr<GrTexture> scratch_textures_[2];
+  int current_texture_;
+  skia::RefPtr<SkGpuDevice> device_;
+  skia::RefPtr<SkCanvas> canvas_;
+};
+
+}  // namespace
+
+WebKit::WebFilterOperations RenderSurfaceFilters::Optimize(
+    const WebKit::WebFilterOperations& filters) {
+  WebKit::WebFilterOperations new_list;
+
+  SkScalar accumulated_color_matrix[20];
+  bool have_accumulated_color_matrix = false;
+  for (unsigned i = 0; i < filters.size(); ++i) {
+    const WebKit::WebFilterOperation& op = filters.at(i);
+
+    // If the filter is a color matrix, we may be able to combine it with
+    // following filter(s) that also are color matrices.
+    SkScalar matrix[20];
+    if (GetColorMatrix(op, matrix)) {
+      if (have_accumulated_color_matrix) {
+        SkScalar newMatrix[20];
+        MultColorMatrix(matrix, accumulated_color_matrix, newMatrix);
+        memcpy(accumulated_color_matrix,
+               newMatrix,
+               sizeof(accumulated_color_matrix));
+      } else {
+        memcpy(accumulated_color_matrix,
+               matrix,
+               sizeof(accumulated_color_matrix));
+        have_accumulated_color_matrix = true;
+      }
+
+      // We can only combine matrices if clamping of color components
+      // would have no effect.
+      if (!MatrixNeedsClamping(accumulated_color_matrix))
+        continue;
+    }
+
+    if (have_accumulated_color_matrix) {
+      new_list.append(WebKit::WebFilterOperation::createColorMatrixFilter(
+          accumulated_color_matrix));
+    }
+    have_accumulated_color_matrix = false;
+
     switch (op.type()) {
-    case WebKit::WebFilterOperation::FilterTypeBrightness: {
-        getBrightnessMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness: {
-        getSaturatingBrightnessMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeContrast: {
-        getContrastMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeGrayscale: {
-        getGrayscaleMatrix(1 - op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeSepia: {
-        getSepiaMatrix(1 - op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeSaturate: {
-        getSaturateMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeHueRotate: {
-        getHueRotateMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeInvert: {
-        getInvertMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeOpacity: {
-        getOpacityMatrix(op.amount(), matrix);
-        return true;
-    }
-    case WebKit::WebFilterOperation::FilterTypeColorMatrix: {
-        memcpy(matrix, op.matrix(), sizeof(SkScalar[20]));
-        return true;
-    }
-    default:
-        return false;
-    }
-}
-
-class FilterBufferState {
-public:
-    FilterBufferState(GrContext* grContext, const gfx::SizeF& size, unsigned textureId)
-        : m_grContext(grContext)
-        , m_currentTexture(0)
-    {
-        // Wrap the source texture in a Ganesh platform texture.
-        GrBackendTextureDesc backendTextureDescription;
-        backendTextureDescription.fWidth = size.width();
-        backendTextureDescription.fHeight = size.height();
-        backendTextureDescription.fConfig = kSkia8888_GrPixelConfig;
-        backendTextureDescription.fTextureHandle = textureId;
-        skia::RefPtr<GrTexture> texture = skia::AdoptRef(grContext->wrapBackendTexture(backendTextureDescription));
-        // Place the platform texture inside an SkBitmap.
-        m_source.setConfig(SkBitmap::kARGB_8888_Config, size.width(), size.height());
-        skia::RefPtr<SkGrPixelRef> pixelRef = skia::AdoptRef(new SkGrPixelRef(texture.get()));
-        m_source.setPixelRef(pixelRef.get());
-    }
-
-    ~FilterBufferState() { }
-
-    bool init(int filterCount)
-    {
-        int scratchCount = std::min(2, filterCount);
-        GrTextureDesc desc;
-        desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
-        desc.fSampleCnt = 0;
-        desc.fWidth = m_source.width();
-        desc.fHeight = m_source.height();
-        desc.fConfig = kSkia8888_GrPixelConfig;
-        for (int i = 0; i < scratchCount; ++i) {
-            GrAutoScratchTexture scratchTexture(m_grContext, desc, GrContext::kExact_ScratchTexMatch);
-            m_scratchTextures[i] = skia::AdoptRef(scratchTexture.detach());
-            if (!m_scratchTextures[i])
-                return false;
-        }
-        return true;
-    }
-
-    SkCanvas* canvas()
-    {
-        if (!m_canvas.get())
-            createCanvas();
-        return m_canvas.get();
-    }
-
-    const SkBitmap& source() { return m_source; }
-
-    void swap()
-    {
-        m_canvas->flush();
-        m_canvas.clear();
-        m_device.clear();
-
-        skia::RefPtr<SkGrPixelRef> pixelRef = skia::AdoptRef(new SkGrPixelRef(m_scratchTextures[m_currentTexture].get()));
-        m_source.setPixelRef(pixelRef.get());
-        m_currentTexture = 1 - m_currentTexture;
-    }
-
-private:
-    void createCanvas()
-    {
-        DCHECK(m_scratchTextures[m_currentTexture].get());
-        m_device = skia::AdoptRef(new SkGpuDevice(m_grContext, m_scratchTextures[m_currentTexture].get()));
-        m_canvas = skia::AdoptRef(new SkCanvas(m_device.get()));
-        m_canvas->clear(0x0);
-    }
-
-    GrContext* m_grContext;
-    SkBitmap m_source;
-    skia::RefPtr<GrTexture> m_scratchTextures[2];
-    int m_currentTexture;
-    skia::RefPtr<SkGpuDevice> m_device;
-    skia::RefPtr<SkCanvas> m_canvas;
-};
-
-}  // namespace
-
-WebKit::WebFilterOperations RenderSurfaceFilters::optimize(const WebKit::WebFilterOperations& filters)
-{
-    WebKit::WebFilterOperations newList;
-
-    SkScalar accumulatedColorMatrix[20];
-    bool haveAccumulatedColorMatrix = false;
-    for (unsigned i = 0; i < filters.size(); ++i) {
-        const WebKit::WebFilterOperation& op = filters.at(i);
-
-        // If the filter is a color matrix, we may be able to combine it with
-        // following filter(s) that also are color matrices.
-        SkScalar matrix[20];
-        if (getColorMatrix(op, matrix)) {
-            if (haveAccumulatedColorMatrix) {
-                SkScalar newMatrix[20];
-                multColorMatrix(matrix, accumulatedColorMatrix, newMatrix);
-                memcpy(accumulatedColorMatrix, newMatrix, sizeof(accumulatedColorMatrix));
-            } else {
-                memcpy(accumulatedColorMatrix, matrix, sizeof(accumulatedColorMatrix));
-                haveAccumulatedColorMatrix = true;
-            }
-
-            // We can only combine matrices if clamping of color components
-            // would have no effect.
-            if (!matrixNeedsClamping(accumulatedColorMatrix))
-                continue;
-        }
-
-        if (haveAccumulatedColorMatrix)
-            newList.append(WebKit::WebFilterOperation::createColorMatrixFilter(accumulatedColorMatrix));
-        haveAccumulatedColorMatrix = false;
-
-        switch (op.type()) {
-        case WebKit::WebFilterOperation::FilterTypeBlur:
-        case WebKit::WebFilterOperation::FilterTypeDropShadow:
-        case WebKit::WebFilterOperation::FilterTypeZoom:
-            newList.append(op);
-            break;
-        case WebKit::WebFilterOperation::FilterTypeBrightness:
-        case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness:
-        case WebKit::WebFilterOperation::FilterTypeContrast:
-        case WebKit::WebFilterOperation::FilterTypeGrayscale:
-        case WebKit::WebFilterOperation::FilterTypeSepia:
-        case WebKit::WebFilterOperation::FilterTypeSaturate:
-        case WebKit::WebFilterOperation::FilterTypeHueRotate:
-        case WebKit::WebFilterOperation::FilterTypeInvert:
-        case WebKit::WebFilterOperation::FilterTypeOpacity:
-        case WebKit::WebFilterOperation::FilterTypeColorMatrix:
-            break;
-        }
-    }
-    if (haveAccumulatedColorMatrix)
-        newList.append(WebKit::WebFilterOperation::createColorMatrixFilter(accumulatedColorMatrix));
-    return newList;
-}
-
-SkBitmap RenderSurfaceFilters::apply(const WebKit::WebFilterOperations& filters, unsigned textureId, gfx::SizeF size, GrContext* grContext)
-{
-    DCHECK(grContext);
-
-    WebKit::WebFilterOperations optimizedFilters = optimize(filters);
-    FilterBufferState state(grContext, size, textureId);
-    if (!state.init(optimizedFilters.size()))
-        return SkBitmap();
-
-    for (unsigned i = 0; i < optimizedFilters.size(); ++i) {
-        const WebKit::WebFilterOperation& op = optimizedFilters.at(i);
-        SkCanvas* canvas = state.canvas();
-        switch (op.type()) {
-        case WebKit::WebFilterOperation::FilterTypeColorMatrix: {
-            SkPaint paint;
-            skia::RefPtr<SkColorMatrixFilter> filter = skia::AdoptRef(new SkColorMatrixFilter(op.matrix()));
-            paint.setColorFilter(filter.get());
-            canvas->drawBitmap(state.source(), 0, 0, &paint);
-            break;
-        }
-        case WebKit::WebFilterOperation::FilterTypeBlur: {
-            float stdDeviation = op.amount();
-            skia::RefPtr<SkImageFilter> filter = skia::AdoptRef(new SkBlurImageFilter(stdDeviation, stdDeviation));
-            SkPaint paint;
-            paint.setImageFilter(filter.get());
-            canvas->drawSprite(state.source(), 0, 0, &paint);
-            break;
-        }
-        case WebKit::WebFilterOperation::FilterTypeDropShadow: {
-            skia::RefPtr<SkImageFilter> blurFilter = skia::AdoptRef(new SkBlurImageFilter(op.amount(), op.amount()));
-            skia::RefPtr<SkColorFilter> colorFilter = skia::AdoptRef(SkColorFilter::CreateModeFilter(op.dropShadowColor(), SkXfermode::kSrcIn_Mode));
-            SkPaint paint;
-            paint.setImageFilter(blurFilter.get());
-            paint.setColorFilter(colorFilter.get());
-            paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
-            canvas->saveLayer(0, &paint);
-            canvas->drawBitmap(state.source(), op.dropShadowOffset().x, -op.dropShadowOffset().y);
-            canvas->restore();
-            canvas->drawBitmap(state.source(), 0, 0);
-            break;
-        }
-        case WebKit::WebFilterOperation::FilterTypeZoom: {
-            SkPaint paint;
-            skia::RefPtr<SkImageFilter> zoomFilter = skia::AdoptRef(
-                new SkMagnifierImageFilter(
-                    SkRect::MakeXYWH(op.zoomRect().x,
-                                     op.zoomRect().y,
-                                     op.zoomRect().width,
-                                     op.zoomRect().height),
-                    op.amount()));
-            paint.setImageFilter(zoomFilter.get());
-            canvas->saveLayer(0, &paint);
-            canvas->drawBitmap(state.source(), 0, 0);
-            canvas->restore();
-            break;
-        }
-        case WebKit::WebFilterOperation::FilterTypeBrightness:
-        case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness:
-        case WebKit::WebFilterOperation::FilterTypeContrast:
-        case WebKit::WebFilterOperation::FilterTypeGrayscale:
-        case WebKit::WebFilterOperation::FilterTypeSepia:
-        case WebKit::WebFilterOperation::FilterTypeSaturate:
-        case WebKit::WebFilterOperation::FilterTypeHueRotate:
-        case WebKit::WebFilterOperation::FilterTypeInvert:
-        case WebKit::WebFilterOperation::FilterTypeOpacity:
-            NOTREACHED();
-            break;
-        }
-        state.swap();
-    }
-    return state.source();
+      case WebKit::WebFilterOperation::FilterTypeBlur:
+      case WebKit::WebFilterOperation::FilterTypeDropShadow:
+      case WebKit::WebFilterOperation::FilterTypeZoom:
+        new_list.append(op);
+        break;
+      case WebKit::WebFilterOperation::FilterTypeBrightness:
+      case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness:
+      case WebKit::WebFilterOperation::FilterTypeContrast:
+      case WebKit::WebFilterOperation::FilterTypeGrayscale:
+      case WebKit::WebFilterOperation::FilterTypeSepia:
+      case WebKit::WebFilterOperation::FilterTypeSaturate:
+      case WebKit::WebFilterOperation::FilterTypeHueRotate:
+      case WebKit::WebFilterOperation::FilterTypeInvert:
+      case WebKit::WebFilterOperation::FilterTypeOpacity:
+      case WebKit::WebFilterOperation::FilterTypeColorMatrix:
+        break;
+    }
+  }
+  if (have_accumulated_color_matrix) {
+    new_list.append(WebKit::WebFilterOperation::createColorMatrixFilter(
+        accumulated_color_matrix));
+  }
+  return new_list;
+}
+
+SkBitmap RenderSurfaceFilters::Apply(const WebKit::WebFilterOperations& filters,
+                                     unsigned texture_id,
+                                     gfx::SizeF size,
+                                     GrContext* gr_context) {
+  DCHECK(gr_context);
+
+  WebKit::WebFilterOperations optimized_filters = Optimize(filters);
+  FilterBufferState state(gr_context, size, texture_id);
+  if (!state.Init(optimized_filters.size()))
+    return SkBitmap();
+
+  for (unsigned i = 0; i < optimized_filters.size(); ++i) {
+    const WebKit::WebFilterOperation& op = optimized_filters.at(i);
+    SkCanvas* canvas = state.Canvas();
+    switch (op.type()) {
+      case WebKit::WebFilterOperation::FilterTypeColorMatrix: {
+        SkPaint paint;
+        skia::RefPtr<SkColorMatrixFilter> filter =
+            skia::AdoptRef(new SkColorMatrixFilter(op.matrix()));
+        paint.setColorFilter(filter.get());
+        canvas->drawBitmap(state.Source(), 0, 0, &paint);
+        break;
+      }
+      case WebKit::WebFilterOperation::FilterTypeBlur: {
+        float std_deviation = op.amount();
+        skia::RefPtr<SkImageFilter> filter =
+            skia::AdoptRef(new SkBlurImageFilter(std_deviation, std_deviation));
+        SkPaint paint;
+        paint.setImageFilter(filter.get());
+        canvas->drawSprite(state.Source(), 0, 0, &paint);
+        break;
+      }
+      case WebKit::WebFilterOperation::FilterTypeDropShadow: {
+        skia::RefPtr<SkImageFilter> blur_filter =
+            skia::AdoptRef(new SkBlurImageFilter(op.amount(), op.amount()));
+        skia::RefPtr<SkColorFilter> color_filter =
+            skia::AdoptRef(SkColorFilter::CreateModeFilter(
+                op.dropShadowColor(), SkXfermode::kSrcIn_Mode));
+        SkPaint paint;
+        paint.setImageFilter(blur_filter.get());
+        paint.setColorFilter(color_filter.get());
+        paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
+        canvas->saveLayer(NULL, &paint);
+        canvas->drawBitmap(state.Source(),
+                           op.dropShadowOffset().x,
+                           -op.dropShadowOffset().y);
+        canvas->restore();
+        canvas->drawBitmap(state.Source(), 0, 0);
+        break;
+      }
+      case WebKit::WebFilterOperation::FilterTypeZoom: {
+        SkPaint paint;
+        skia::RefPtr<SkImageFilter> zoom_filter = skia::AdoptRef(
+            new SkMagnifierImageFilter(
+                SkRect::MakeXYWH(op.zoomRect().x,
+                                 op.zoomRect().y,
+                                 op.zoomRect().width,
+                                 op.zoomRect().height),
+                op.amount()));
+        paint.setImageFilter(zoom_filter.get());
+        canvas->saveLayer(NULL, &paint);
+        canvas->drawBitmap(state.Source(), 0, 0);
+        canvas->restore();
+        break;
+      }
+      case WebKit::WebFilterOperation::FilterTypeBrightness:
+      case WebKit::WebFilterOperation::FilterTypeSaturatingBrightness:
+      case WebKit::WebFilterOperation::FilterTypeContrast:
+      case WebKit::WebFilterOperation::FilterTypeGrayscale:
+      case WebKit::WebFilterOperation::FilterTypeSepia:
+      case WebKit::WebFilterOperation::FilterTypeSaturate:
+      case WebKit::WebFilterOperation::FilterTypeHueRotate:
+      case WebKit::WebFilterOperation::FilterTypeInvert:
+      case WebKit::WebFilterOperation::FilterTypeOpacity:
+        NOTREACHED();
+        break;
+    }
+    state.Swap();
+  }
+  return state.Source();
 }
 
 }  // namespace cc