Adds a bounds parameter to ui::Compositor::ReadPixels

ui/gfx/compositor/compositor_cc.cc

 // Copyright (c) 2011 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 "ui/gfx/compositor/compositor_cc.h"
 
 #include "third_party/skia/include/images/SkImageEncoder.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositor.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFloatPoint.h"
@@ skipping 164 matching lines @@
 void CompositorCC::OnRootLayerChanged() {
   root_web_layer_.removeAllChildren();
   if (root_layer())
     root_web_layer_.addChild(root_layer()->web_layer());
 }
 
 void CompositorCC::DrawTree() {
   host_.composite();
 }
 
-bool CompositorCC::ReadPixels(SkBitmap* bitmap) {
+bool CompositorCC::ReadPixels(SkBitmap* bitmap, const gfx::Rect& bounds) {
+  if (bounds.right() > size().width() || bounds.bottom() > size().height())
+    return false;
+  // Convert to Skia coordinates.
+  gfx::Point new_origin(bounds.x(),
+                        size().height() - bounds.height() - bounds.y());
+
   bitmap->setConfig(SkBitmap::kARGB_8888_Config,
-                    size().width(), size().height());
+                    bounds.width(), bounds.height());
   bitmap->allocPixels();
   SkAutoLockPixels lock_image(*bitmap);
   unsigned char* pixels = static_cast<unsigned char*>(bitmap->getPixels());
-  if (host_.compositeAndReadback(pixels, gfx::Rect(size()))) {
-    SwizzleRGBAToBGRAAndFlip(pixels, size());
+  if (host_.compositeAndReadback(pixels,
+                                 gfx::Rect(new_origin, bounds.size()))) {
+    SwizzleRGBAToBGRAAndFlip(pixels, bounds.size());
     return true;
   }
   return false;
 }
 
 void CompositorCC::animateAndLayout(double frameBeginTime) {
 }
 
 void CompositorCC::applyScrollAndScale(const WebKit::WebSize& scrollDelta,
                                        float scaleFactor) {
@@ skipping 23 matching lines @@
   ScheduleDraw();
 }
 
 Compositor* Compositor::Create(CompositorDelegate* owner,
                                gfx::AcceleratedWidget widget,
                                const gfx::Size& size) {
   return new CompositorCC(owner, widget, size);
 }
 
 }  // namespace ui