[Contextual Search] Add support for crushed sprites and animate the search provider icon

chrome/browser/android/compositor/layer/crushed_sprite_layer.cc

+// Copyright 2015 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 "chrome/browser/android/compositor/layer/crushed_sprite_layer.h"
+
+#include "cc/layers/layer.h"
+#include "cc/layers/ui_resource_layer.h"
+#include "content/public/browser/android/compositor.h"
+#include "ui/android/resources/crushed_sprite_resource.h"
+#include "ui/android/resources/resource_manager.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/skia_util.h"
+
+namespace chrome {
+namespace android {
+
+// static
+scoped_refptr<CrushedSpriteLayer> CrushedSpriteLayer::Create() {
+  return make_scoped_refptr(new CrushedSpriteLayer());
+}
+
+scoped_refptr<cc::Layer> CrushedSpriteLayer::layer() {
+  return layer_;
+}
+
+void CrushedSpriteLayer::DrawSpriteFrame(
+    ui::ResourceManager* resource_manager,
+    int bitmap_res_id,
+    int metadata_res_id,
+    float completion_percentage) {
+  DCHECK(completion_percentage >= 0.f && completion_percentage <= 1.f);
+
+  int sprite_frame = completion_percentage * (frame_count_ - 1);
+
+  if (frame_count_ == -1 || sprite_frame != previous_frame_) {

[David Trainor- moved to gerrit, 2015/10/27 21:00:42]

Do we need frame_count_ == -1 if previous_frame will start at -1?

[Theresa, 2015/10/27 21:24:49]

Maybe.. if the completion percentage starts at .5 then sprite_frame = .5 * (-1 -
1) = -1 

That seems unlikely but better safe than sorry?

+    // Get resource and setup variables.
+    ui::CrushedSpriteResource* resource =
+        resource_manager->GetCrushedSpriteResource(
+            bitmap_res_id,
+            metadata_res_id);
+    frame_count_ = resource->GetFrameCount();

[David Trainor- moved to gerrit, 2015/10/27 21:00:42]

Move up above the other sprite_frame

[Theresa, 2015/10/27 21:24:49]

It's here on purpose. If we're redisplaying the last frame (and do nothing) we
don't want to call GetCrushedSpriteResource or the bitmap will (possibly) be
reloaded. But we need to at least try to calculate the sprite_frame to know if
we're redisplaying.

+    int sprite_frame = completion_percentage * (frame_count_ - 1);

[David Trainor- moved to gerrit, 2015/10/27 21:00:43]

redundant?

[Theresa, 2015/10/27 21:24:49]

If frame_count_ != -1, yes. I'll surround this line and the one above it with
that check before recalculating.

[Theresa, 2015/10/28 02:01:53]

Done.

+
+
+    // Reset the previous_frame if the animation is being re-run.
+    if (previous_frame_ > sprite_frame) {
+      previous_frame_ = 0;
+    }
+
+    // Set up an SkCanvas backed by an SkBitmap to draw into.
+    SkBitmap bitmap;
+    bitmap.allocN32Pixels(resource->GetSpriteSize().width(),
+                           resource->GetSpriteSize().height());
+    skia::RefPtr<SkCanvas> canvas = skia::AdoptRef(new SkCanvas(bitmap));
+
+    // If this isn't the first or last frame, draw the previous frame(s).
+    // Note(twellington): This assumes that the last frame in the crushed sprite
+    // animation does not require any previous frames drawn before it. This code
+    // needs to be updated if crushed sprites are added for which this
+    // assumption does not hold.
+    if (sprite_frame != 0 && sprite_frame != resource->GetFrameCount() - 1) {
+      // Draw the previous frame.
+      canvas->drawBitmap(previous_frame_bitmap_, 0, 0, nullptr);
+
+      // Draw any skipped frames.
+      for (int i = previous_frame_ + 1; i < sprite_frame; ++i) {
+        DrawRectanglesForFrame(resource, i, canvas);
+      }
+    }
+
+    // Draw the current frame.
+    DrawRectanglesForFrame(resource, sprite_frame, canvas);
+
+    // Set the bitmap on layer_.
+    bitmap.setImmutable();
+    layer_->SetBitmap(bitmap);
+
+    // Evict the crushed sprite bitmap from memory if this is the last frame.
+    if (sprite_frame == frame_count_ - 1) {
+      resource->GetBitmap().empty();

[David Trainor- moved to gerrit, 2015/10/27 21:00:42]

Doesn't this just return if it's empty?  Also do we want to drop the SkBitmap
completely?

[Theresa, 2015/10/27 21:24:49]

Discussed offline, I'll use .reset() and add a method to the resource itself to
evict the spritesheet.

[Theresa, 2015/10/28 02:01:53]

Done.

+    }
+
+    // Update previous_frame_* variables.
+    previous_frame_bitmap_ = bitmap;
+    previous_frame_ = sprite_frame;
+  }
+}
+
+void CrushedSpriteLayer::DrawRectanglesForFrame(
+    ui::CrushedSpriteResource* resource,
+    int frame,
+    skia::RefPtr<SkCanvas> canvas) {
+  ui::CrushedSpriteResource::FrameSrcDstRects src_dst_rects =
+       resource->GetRectanglesForFrame(frame);
+  for (const auto& rect : src_dst_rects) {
+    canvas->drawBitmapRect(resource->GetBitmap(),
+                           gfx::RectToSkRect(rect.first),
+                           gfx::RectToSkRect(rect.second),
+                           nullptr);
+  }
+}
+
+CrushedSpriteLayer::CrushedSpriteLayer()
+    : layer_(
+          cc::UIResourceLayer::Create(content::Compositor::LayerSettings())),
+      frame_count_(-1),
+      previous_frame_(-1) {
+  layer_->SetIsDrawable(true);
+}
+
+
+CrushedSpriteLayer::~CrushedSpriteLayer() {
+}
+
+}  // namespace android
+}  // namespace chrome