Add some optimizations to plugin painting.

The simplest one is to disable blending when the plugin is opaque. The more
complicated one is to bypass webkit painting the background of plugins when we
know the plugin to be always on top and also opaque. The always on top flag is
currently set by a new "Private2" API. Bypassing WebKit makes animations
faster.

This is a re-land of the previous patch with a trivial compilation fix. This
also adds a clip rect to the GetBitmap... function so we can properly handle
plugins in nested iframes with proper clipping.

BUG=none
TEST=none
Original review URL: http://codereview.chromium.org/3421030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60426 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 91 insertions, 5 deletions

diff --git a/chrome/renderer/pepper_plugin_delegate_impl.cc b/chrome/renderer/pepper_plugin_delegate_impl.cc
index 7ca9d4e..31b89ff 100644
--- a/chrome/renderer/pepper_plugin_delegate_impl.cc
+++ b/chrome/renderer/pepper_plugin_delegate_impl.cc
@@ -53,6 +53,10 @@ class PlatformImage2DImpl : public pepper::PluginDelegate::PlatformImage2D {
     return reinterpret_cast<intptr_t>(dib_.get());
   }
 
+  virtual TransportDIB* GetTransportDIB() const {
+    return dib_.get();
+  }
+
  private:
   int width_;
   int height_;
@@ -520,6 +524,22 @@ void PepperPluginDelegateImpl::ViewFlushedPaint() {
   }
 }
 
+bool PepperPluginDelegateImpl::GetBitmapForOptimizedPluginPaint(
+    const gfx::Rect& paint_bounds,
+    TransportDIB** dib,
+    gfx::Rect* location,
+    gfx::Rect* clip) {
+  for (std::set<pepper::PluginInstance*>::iterator i =
+           active_instances_.begin();
+       i != active_instances_.end(); ++i) {
+    pepper::PluginInstance* instance = *i;
+    if (instance->GetBitmapForOptimizedPluginPaint(
+            paint_bounds, dib, location, clip))
+      return true;
+  }
+  return false;
+}
+
 void PepperPluginDelegateImpl::InstanceCreated(
     pepper::PluginInstance* instance) {
   active_instances_.insert(instance);
diff --git a/chrome/renderer/pepper_plugin_delegate_impl.h b/chrome/renderer/pepper_plugin_delegate_impl.h
index a5808d5..8bacb44 100644
--- a/chrome/renderer/pepper_plugin_delegate_impl.h
+++ b/chrome/renderer/pepper_plugin_delegate_impl.h
@@ -19,6 +19,10 @@
 class FilePath;
 class RenderView;
 
+namespace gfx {
+class Rect;
+}
+
 namespace pepper {
 class FileIO;
 class PluginInstance;
@@ -29,6 +33,8 @@ class WebFileChooserCompletion;
 struct WebFileChooserParams;
 }
 
+class TransportDIB;
+
 class PepperPluginDelegateImpl
     : public pepper::PluginDelegate,
       public base::SupportsWeakPtr<PepperPluginDelegateImpl> {
@@ -41,6 +47,14 @@ class PepperPluginDelegateImpl
   void ViewInitiatedPaint();
   void ViewFlushedPaint();
 
+  // Called by RenderView to implement the corresponding function in its base
+  // class RenderWidget (see that for more).
+  bool GetBitmapForOptimizedPluginPaint(
+      const gfx::Rect& paint_bounds,
+      TransportDIB** dib,
+      gfx::Rect* location,
+      gfx::Rect* clip);
+
   // Called by RenderView when ViewMsg_AsyncOpenFile_ACK.
   void OnAsyncFileOpened(base::PlatformFileError error_code,
                          base::PlatformFile file,
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index 9666b67..98fa378 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -4728,6 +4728,15 @@ void RenderView::DidFlushPaint() {
   }
 }
 
+bool RenderView::GetBitmapForOptimizedPluginPaint(
+    const gfx::Rect& paint_bounds,
+    TransportDIB** dib,
+    gfx::Rect* location,
+    gfx::Rect* clip) {
+  return pepper_delegate_.GetBitmapForOptimizedPluginPaint(
+      paint_bounds, dib, location, clip);
+}
+
 void RenderView::OnClearFocusedNode() {
   if (webview())
     webview()->clearFocusedNode();
diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index f0dad4d4..f267de6 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -619,6 +619,11 @@ class RenderView : public RenderWidget,
                         const gfx::Rect& resizer_rect);
   virtual void DidInitiatePaint();
   virtual void DidFlushPaint();
+  virtual bool GetBitmapForOptimizedPluginPaint(
+      const gfx::Rect& paint_bounds,
+      TransportDIB** dib,
+      gfx::Rect* location,
+      gfx::Rect* clip);
   virtual void DidHandleKeyEvent();
   virtual void DidHandleMouseEvent(const WebKit::WebMouseEvent& event);
   virtual void OnSetFocus(bool enable);
diff --git a/chrome/renderer/render_widget.cc b/chrome/renderer/render_widget.cc
index 3252097..f5a7ebe 100644
--- a/chrome/renderer/render_widget.cc
+++ b/chrome/renderer/render_widget.cc
@@ -505,11 +505,24 @@ void RenderWidget::DoDeferredUpdate() {
   gfx::Rect scroll_damage = update.GetScrollDamage();
   gfx::Rect bounds = update.GetPaintBounds().Union(scroll_damage);
 
+  // A plugin may be able to do an optimized paint. First check this, in which
+  // case we can skip all of the bitmap generation and regular paint code.
+  TransportDIB::Id dib_id = TransportDIB::Id();
+  TransportDIB* dib = NULL;
   std::vector<gfx::Rect> copy_rects;
-  if (!is_gpu_rendering_active_) {
+  gfx::Rect optimized_copy_rect, optimized_copy_location;
+  if (update.scroll_rect.IsEmpty() &&
+      !is_gpu_rendering_active_ &&
+      GetBitmapForOptimizedPluginPaint(bounds, &dib, &optimized_copy_location,
+                                       &optimized_copy_rect)) {
+    bounds = optimized_copy_location;
+    copy_rects.push_back(optimized_copy_rect);
+    dib_id = dib->id();
+  } else if (!is_gpu_rendering_active_) {
     // Compute a buffer for painting and cache it.
-    scoped_ptr<skia::PlatformCanvas> canvas
-      (RenderProcess::current()->GetDrawingCanvas(&current_paint_buf_, bounds));
+    scoped_ptr<skia::PlatformCanvas> canvas(
+        RenderProcess::current()->GetDrawingCanvas(&current_paint_buf_,
+                                                   bounds));
     if (!canvas.get()) {
       NOTREACHED();
       return;
@@ -538,6 +551,8 @@ void RenderWidget::DoDeferredUpdate() {
 
     for (size_t i = 0; i < copy_rects.size(); ++i)
       PaintRect(copy_rects[i], bounds.origin(), canvas.get());
+
+    dib_id = current_paint_buf_->id();
   } else {  // Accelerated compositing path
     // Begin painting.
     bool finish = next_paint_is_resize_ack();
@@ -546,8 +561,7 @@ void RenderWidget::DoDeferredUpdate() {
 
   // sending an ack to browser process that the paint is complete...
   ViewHostMsg_UpdateRect_Params params;
-  params.bitmap =
-      current_paint_buf_ ? current_paint_buf_->id() : TransportDIB::Id();
+  params.bitmap = dib_id;
   params.bitmap_rect = bounds;
   params.dx = update.scroll_delta.x();
   params.dy = update.scroll_delta.y();
@@ -889,6 +903,15 @@ void RenderWidget::OnSetTextDirection(WebTextDirection direction) {
   webwidget_->setTextDirection(direction);
 }
 
+bool RenderWidget::GetBitmapForOptimizedPluginPaint(
+    const gfx::Rect& paint_bounds,
+    TransportDIB** dib,
+    gfx::Rect* location,
+    gfx::Rect* clip) {
+  // Normal RenderWidgets don't support optimized plugin painting.
+  return false;
+}
+
 void RenderWidget::SetHidden(bool hidden) {
   if (is_hidden_ == hidden)
     return;
diff --git a/chrome/renderer/render_widget.h b/chrome/renderer/render_widget.h
index 6d80b62..e1dacf3 100644
--- a/chrome/renderer/render_widget.h
+++ b/chrome/renderer/render_widget.h
@@ -201,6 +201,21 @@ class RenderWidget : public IPC::Channel::Listener,
   virtual void DidInitiatePaint() {}
   virtual void DidFlushPaint() {}
 
+  // Detects if a suitable opaque plugin covers the given paint bounds with no
+  // compositing necessary.
+  //
+  // Returns true if the paint can be handled by just blitting the plugin
+  // bitmap. In this case, the location, clipping, and ID of the backing store
+  // will be filled into the given output parameters.
+  //
+  // A return value of false means optimized painting can not be used and we
+  // should continue with the normal painting code path.
+  virtual bool GetBitmapForOptimizedPluginPaint(
+      const gfx::Rect& paint_bounds,
+      TransportDIB** dib,
+      gfx::Rect* location,
+      gfx::Rect* clip);
+
   // Sets the "hidden" state of this widget.  All accesses to is_hidden_ should
   // use this method so that we can properly inform the RenderThread of our
   // state.