[WIP] Import all canvas layers, rather than just topmost

android_webview/browser/in_process_view_renderer.cc

Index: android_webview/browser/in_process_view_renderer.cc
diff --git a/android_webview/browser/in_process_view_renderer.cc b/android_webview/browser/in_process_view_renderer.cc
index 39614d38ce1393af606cafa4e60e686e277382c2..742d89cbf0d325df9e876b2cee624dc4074a5892 100644
--- a/android_webview/browser/in_process_view_renderer.cc
+++ b/android_webview/browser/in_process_view_renderer.cc
@@ -423,79 +423,102 @@ bool InProcessViewRenderer::DrawSWInternal(jobject java_canvas,
       web_contents_);
 }
 
-// static
-bool InProcessViewRenderer::RenderViaAuxilaryBitmapIfNeeded(
-      jobject java_canvas,
-      BrowserViewRenderer::JavaHelper* java_helper,
-      const gfx::Vector2d& scroll_correction,
-      const gfx::Rect& clip,
-      InProcessViewRenderer::RenderMethod render_source,
-      void* owner_key) {
-  TRACE_EVENT0("android_webview",
-               "InProcessViewRenderer::RenderViaAuxilaryBitmapIfNeeded");
-
-  JNIEnv* env = AttachCurrentThread();
-  ScopedPixelAccess auto_release_pixels(env, java_canvas);
-  AwPixelInfo* pixels = auto_release_pixels.pixels();
-  SkMatrix matrix;
-  SkBitmap::Config config(SkBitmap::kNo_Config);
-  if (pixels) {
-    switch (pixels->config) {
-      case AwConfig_ARGB_8888:
-        config = SkBitmap::kARGB_8888_Config;
-        break;
-      case AwConfig_RGB_565:
-        config = SkBitmap::kRGB_565_Config;
-        break;
-    }
+namespace {
 
-    for (int i = 0; i < 9; i++) {
-      matrix.set(i, pixels->matrix[i]);
-    }
-    // Workaround for http://crbug.com/271096: SW draw only supports
-    // translate & scale transforms.
-    if (matrix.getType() & ~(SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask))
-      config = SkBitmap::kNo_Config;
-  }
-
-  if (config == SkBitmap::kNo_Config) {
-    // Render into an auxiliary bitmap if pixel info is not available.
-    ScopedJavaLocalRef<jobject> jcanvas(env, java_canvas);
-    TRACE_EVENT0("android_webview", "RenderToAuxBitmap");
-    ScopedJavaLocalRef<jobject> jbitmap(java_helper->CreateBitmap(
-        env, clip.width(), clip.height(), jcanvas, owner_key));
-    if (!jbitmap.obj()) {
-      TRACE_EVENT_INSTANT0("android_webview",
-                           "EarlyOut_BitmapAllocFail",
-                           TRACE_EVENT_SCOPE_THREAD);
+struct LayerImportState {
+  bool SetBitmap(const AwBitmapInfo& info) {
+    SkBitmap::Config config =
+        info.config == AwConfig_ARGB_8888 ? SkBitmap::kARGB_8888_Config :
+        info.config == AwConfig_RGB_565 ? SkBitmap::kRGB_565_Config :
+        SkBitmap::kNo_Config;
+    if (config == SkBitmap::kNo_Config)
       return false;
-    }
+    bitmap.setConfig(config, info.width, info.height, info.row_bytes);
+    bitmap.setPixels(info.pixels);
 
-    if (!RasterizeIntoBitmap(env, jbitmap,
-                             clip.x() - scroll_correction.x(),
-                             clip.y() - scroll_correction.y(),
-                             render_source)) {
-      TRACE_EVENT_INSTANT0("android_webview",
-                           "EarlyOut_RasterizeFail",
-                           TRACE_EVENT_SCOPE_THREAD);
-      return false;
+    LOG(WARNING) << "JOTH decode:  " << info.x << ", " << info.y
+        << ", " << info.width << ", " << info.height;
+    return true;
+  }
+  SkBitmap bitmap;
+  bool importing;
+};
+
+class LayerImportDevice : public SkDevice {
+ public:
+  LayerImportDevice(const LayerImportState* state)
+      : SkDevice(state->bitmap),
+        state_(state) {
+    DCHECK(state_->importing);
+  }
+
+  SkDevice* onCreateCompatibleDevice(SkBitmap::Config config,
+                                     int width, int height,
+                                     bool isOpaque,
+                                     Usage usage) {
+    const SkBitmap& bitmap = state_->bitmap;
+    if (!state_->importing) {
+      DCHECK(bitmap.empty() && state_->bitmap.isNull());
+      return new SkDevice(config, width, height, isOpaque);
     }
+    DCHECK(usage != SkDevice::kGeneral_Usage);
+    DCHECK(bitmap.config() == config);
+    DCHECK(bitmap.width() == width);
+    DCHECK(bitmap.height() == height);
+    DCHECK(width == 0 || height == 0 || !bitmap.isNull());
+    return new LayerImportDevice(state_);
+  }
 
-    java_helper->DrawBitmapIntoCanvas(env, jbitmap, jcanvas,
-                                      clip.x(), clip.y());
-    return true;
+ private:
+  const LayerImportState* state_;
+};
+
+bool RenderDirectToCanvas(JNIEnv* env,
+                          jobject java_canvas,
+                          BrowserViewRenderer::JavaHelper* java_helper,
+                          const gfx::Vector2d& scroll_correction,
+                          InProcessViewRenderer::RenderMethod render_source) {
+  ScopedPixelAccess auto_release_pixels(env, java_canvas);
+  AwPixelInfo* pixels = auto_release_pixels.pixels();
+  if (!pixels)
+    return false;
+
+  SkMatrix matrix;
+  for (int i = 0; i < 9; i++) {
+    matrix.set(i, pixels->matrix[i]);
   }
+  // Workarounds for http://crbug.com/271096: SW draw only supports
+  // translate & scale transforms, and a simple rectangular clip.
+  if (matrix.getType() & ~(SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask))
+    return false;
+  if (pixels->clip_rect_count > 1)
+    return false;
 
   // Draw in a SkCanvas built over the pixel information.
-  SkBitmap bitmap;
-  bitmap.setConfig(config,
-                   pixels->width,
-                   pixels->height,
-                   pixels->row_bytes);
-  bitmap.setPixels(pixels->pixels);
-  SkDevice device(bitmap);
+  if (pixels->layer_count < 1)
+    return false;
+  LayerImportState layer;
+  layer.importing = true;
+  if (!layer.SetBitmap(pixels->layers[0]))
+    return false;
+  LayerImportDevice device(&layer);
   SkCanvas canvas(&device);
-  canvas.setMatrix(matrix);
+
+  // Iterate over the layers above the root (hence, starting a 1).
+  for (int i = 1; i < pixels->layer_count; ++i) {
+    const AwBitmapInfo& bitmap = pixels->layers[i];
+    layer.SetBitmap(bitmap);
+    SkRect rect = SkRect::MakeXYWH(bitmap.x, bitmap.y,
+                                   bitmap.width, bitmap.height);
+    // Use a "dest" xfer so that our shadow-layer stack restore is a no-op.
+    SkPaint dest_mode;
+    dest_mode.setXfermodeMode(SkXfermode::kDst_Mode);
+    canvas.saveLayer(&rect, &dest_mode, SkCanvas::kARGB_NoClipLayer_SaveFlag);
+    DCHECK(canvas.getTopDevice()->getOrigin() ==
+           SkIPoint::Make(bitmap.x, bitmap.y));
+  }
+  layer.bitmap.reset();
+  layer.importing = false;
 
   if (pixels->clip_rect_count) {
     SkRegion clip;
@@ -508,13 +531,60 @@ bool InProcessViewRenderer::RenderViaAuxilaryBitmapIfNeeded(
     }
     canvas.setClipRegion(clip);
   }
-
+  canvas.setMatrix(matrix);
   canvas.translate(scroll_correction.x(),
                    scroll_correction.y());
 
   return render_source.Run(&canvas);
 }
 
+}  // namespace
+
+bool InProcessViewRenderer::RenderViaAuxilaryBitmapIfNeeded(
+      jobject java_canvas,
+      BrowserViewRenderer::JavaHelper* java_helper,
+      const gfx::Vector2d& scroll_correction,
+      const gfx::Rect& clip,
+      InProcessViewRenderer::RenderMethod render_source,
+      void* owner_key) {
+  TRACE_EVENT0("android_webview",
+               "InProcessViewRenderer::RenderViaAuxilaryBitmapIfNeeded");
+
+  JNIEnv* env = AttachCurrentThread();
+  if (RenderDirectToCanvas(env,
+                           java_canvas,
+                           java_helper,
+                           scroll_correction,
+                           render_source)) {
+   return true;
+  }
+  // Render into an auxiliary bitmap if pixel info is not available.
+  ScopedJavaLocalRef<jobject> jcanvas(env, java_canvas);
+  TRACE_EVENT0("android_webview", "RenderToAuxBitmap");
+  ScopedJavaLocalRef<jobject> jbitmap(java_helper->CreateBitmap(
+      env, clip.width(), clip.height(), jcanvas, owner_key));
+  if (!jbitmap.obj()) {
+    TRACE_EVENT_INSTANT0("android_webview",
+                         "EarlyOut_BitmapAllocFail",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return false;
+  }
+
+  if (!RasterizeIntoBitmap(env, jbitmap,
+                           clip.x() - scroll_correction.x(),
+                           clip.y() - scroll_correction.y(),
+                           render_source)) {
+    TRACE_EVENT_INSTANT0("android_webview",
+                         "EarlyOut_RasterizeFail",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return false;
+  }
+
+  java_helper->DrawBitmapIntoCanvas(env, jbitmap, jcanvas,
+                                    clip.x(), clip.y());
+  return true;
+}
+
 skia::RefPtr<SkPicture> InProcessViewRenderer::CapturePicture(int width,
                                                               int height) {
   TRACE_EVENT0("android_webview", "InProcessViewRenderer::CapturePicture");