Cache auxiliary bitmap across draw frames

android_webview/browser/in_process_renderer/in_process_view_renderer.cc

 // Copyright (c) 2013 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 "android_webview/browser/in_process_renderer/in_process_view_renderer.h"
 
 #include <android/bitmap.h>
 
 #include "android_webview/public/browser/draw_gl.h"
 #include "android_webview/public/browser/draw_sw.h"
 #include "base/android/jni_android.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "content/public/browser/android/content_view_core.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/renderer/android/synchronous_compositor.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkGraphics.h"
 #include "third_party/skia/include/core/SkPicture.h"
@@ skipping 217 matching lines @@
                                    const gfx::Rect& clip) {
   bool result = DrawSWInternal(java_canvas, clip);
   EnsureContinuousInvalidation();
   return result;
 }
 
 bool InProcessViewRenderer::DrawSWInternal(jobject java_canvas,
                                            const gfx::Rect& clip) {
   TRACE_EVENT0("android_webview", "InProcessViewRenderer::DrawSW");
 
-  if (clip.IsEmpty())
+  if (clip.IsEmpty()) {
+    TRACE_EVENT_INSTANT0("android_webview", "Empty Clip",
+                         TRACE_EVENT_SCOPE_THREAD);
     return true;
+  }
 
   JNIEnv* env = AttachCurrentThread();
 
   AwDrawSWFunctionTable* sw_functions = GetAwDrawSWFunctionTable();
   AwPixelInfo* pixels = sw_functions ?
       sw_functions->access_pixels(env, java_canvas) : NULL;
   // Render into an auxiliary bitmap if pixel info is not available.
   if (pixels == NULL) {
+    TRACE_EVENT0("android_webview", "Render to Aux Bitmap");
     ScopedJavaLocalRef<jobject> jbitmap(java_helper_->CreateBitmap(
-        env, clip.width(), clip.height()));
-    if (!jbitmap.obj())
+        env, clip.width(), clip.height(), true));
+    if (!jbitmap.obj()) {
+      TRACE_EVENT_INSTANT0("android_webview", "Bitmap Alloc Fail",
+                           TRACE_EVENT_SCOPE_THREAD);
       return false;
+    }
 
     if (!RasterizeIntoBitmap(env, jbitmap, clip.x(), clip.y(),
                              base::Bind(&InProcessViewRenderer::RenderSW,
                                         base::Unretained(this)))) {
+      TRACE_EVENT_INSTANT0("android_webview", "Rasterize Fail",
+                           TRACE_EVENT_SCOPE_THREAD);
       return false;
     }
 
     ScopedJavaLocalRef<jobject> jcanvas(env, java_canvas);
     java_helper_->DrawBitmapIntoCanvas(env, jbitmap, jcanvas);
     return true;
   }
 
   // Draw in a SkCanvas built over the pixel information.
   bool succeeded = false;
@@ skipping 50 matching lines @@
   picture->endRecording();
 
   if (IsSkiaVersionCompatible()) {
     // Add a reference that the create_picture() will take ownership of.
     picture->ref();
     return ScopedJavaLocalRef<jobject>(env,
         GetAwDrawSWFunctionTable()->create_picture(env, picture.get()));
   }
 
   // If Skia versions are not compatible, workaround it by rasterizing the
-  // picture into a bitmap and drawing it into a new Java picture.
+  // picture into a bitmap and drawing it into a new Java picture. Pass false
+  // for |cache_result| as the picture we create will hold a shallow reference
+  // to the bitmap drawn, and we don't want subsequent draws to corrupt any
+  // previously returned pictures.
   ScopedJavaLocalRef<jobject> jbitmap(java_helper_->CreateBitmap(
-      env, picture->width(), picture->height()));
+      env, picture->width(), picture->height(), false));
   if (!jbitmap.obj())
     return ScopedJavaLocalRef<jobject>();
 
   if (!RasterizeIntoBitmap(env, jbitmap, 0, 0,
       base::Bind(&RenderPictureToCanvas,
                  base::Unretained(picture.get())))) {
     return ScopedJavaLocalRef<jobject>();
   }
 
   return java_helper_->RecordBitmapIntoPicture(env, jbitmap);
@@ skipping 73 matching lines @@
   // TODO(joth): BrowserViewRendererImpl had a bunch of logic for dpi and page
   // scale here. Determine what if any needs bringing over to this class.
   return CompositeSW(canvas);
 }
 
 bool InProcessViewRenderer::CompositeSW(SkCanvas* canvas) {
   return compositor_ && compositor_->DemandDrawSw(canvas);
 }
 
 }  // namespace android_webview