Add transparency support to RenderWidgetHostView.

This is used to make the background behind toolstrips 'shine
through' them. It isn't possible to make them really transparent
due to cleartype (cleartype must know the pixels behind the text
to work), so instead we paint the background we want behind the
transparent webview.

Review URL: http://codereview.chromium.org/88076

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14378 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 64 insertions, 7 deletions

diff --git a/chrome/browser/views/bookmark_bar_view.cc b/chrome/browser/views/bookmark_bar_view.cc
index b0be7dd..b5298db 100644
--- a/chrome/browser/views/bookmark_bar_view.cc
+++ b/chrome/browser/views/bookmark_bar_view.cc
@@ -17,6 +17,8 @@
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/metrics/user_metrics.h"
 #include "chrome/browser/profile.h"
+#include "chrome/browser/renderer_host/render_view_host.h"
+#include "chrome/browser/renderer_host/render_widget_host_view.h"
 #include "chrome/browser/tab_contents/page_navigator.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/view_ids.h"
@@ -297,20 +299,16 @@ class BookmarkFolderButton : public views::MenuButton {
 // A simple container with a border for an ExtensionView.
 class ExtensionToolstrip : public views::View {
  public:
-  static const int kPadding = 2;
-
   ExtensionToolstrip(Extension* extension, const GURL& url, Browser* browser)
       : view_(browser->profile()->GetExtensionsService()->CreateView(
           extension, url, browser)) {
     AddChildView(view_);
-    set_border(views::Border::CreateEmptyBorder(
-        kPadding, kPadding, kPadding, kPadding));
   }
 
+  ExtensionView* view() { return view_; }
+
   virtual gfx::Size GetPreferredSize() {
-    gfx::Size size = view_->GetPreferredSize();
-    size.Enlarge(kPadding*2, kPadding*2);
-    return size;
+    return view_->GetPreferredSize();
   }
 
   virtual void DidChangeBounds(const gfx::Rect& previous,
@@ -689,6 +687,13 @@ void BookmarkBarView::Paint(ChromeCanvas* canvas) {
     canvas->drawRoundRect(rect,
                           SkDoubleToScalar(roundness),
                           SkDoubleToScalar(roundness), border_paint);
+
+    SkRect toolstrip_background_rect = {
+        rect.fLeft + 1 + kNewtabBarRoundness,
+        rect.fTop + 1,
+        rect.fLeft + 1 + kNewtabBarRoundness + 1,
+        rect.fBottom - 1};
+    InitToolstripBackground(canvas, toolstrip_background_rect);
   } else {
     SkPaint paint;
     paint.setShader(skia::CreateGradientShader(0,
@@ -699,6 +704,51 @@ void BookmarkBarView::Paint(ChromeCanvas* canvas) {
 
     canvas->FillRectInt(kTopBorderColor, 0, 0, width(), 1);
     canvas->FillRectInt(kBottomBorderColor, 0, height() - 1, width(), 1);
+
+    SkRect toolstrip_background_rect = {
+        SkIntToScalar(0),
+        SkIntToScalar(1),
+        SkIntToScalar(1),
+        SkIntToScalar(height() - 2)};
+    InitToolstripBackground(canvas, toolstrip_background_rect);
+  }
+}
+
+void BookmarkBarView::InitToolstripBackground(ChromeCanvas* canvas,
+                                              const SkRect& subset) {
+  if (!toolstrip_background_.empty())
+    return;
+
+  const SkBitmap& bookmarkbar_background =
+      canvas->getDevice()->accessBitmap(false);
+
+  // Extract the correct subset of the toolstrip background into a bitmap. We
+  // must use a temporary here because extractSubset() returns a bitmap that
+  // references pixels in the original one and we want to actually make a copy
+  // that will have a long lifetime.
+  SkBitmap temp;
+  temp.setConfig(bookmarkbar_background.config(),
+                 static_cast<int>(subset.width()),
+                 static_cast<int>(subset.height()));
+
+  SkRect mapped_subset = subset;
+  bool result = canvas->getTotalMatrix().mapRect(&mapped_subset);
+  DCHECK(result);
+
+  SkIRect isubset;
+  mapped_subset.round(&isubset);
+  result = bookmarkbar_background.extractSubset(&temp, isubset);
+  if (!result)
+    return;
+
+  temp.copyTo(&toolstrip_background_, temp.config());
+  DCHECK(toolstrip_background_.readyToDraw());
+
+  // Tell all current toolstrips about the new background
+  for (int i = GetBookmarkButtonCount();
+       i < GetBookmarkButtonCount() + num_extension_toolstrips_; ++i) {
+    static_cast<ExtensionToolstrip*>(GetChildViewAt(i))->view()->SetBackground(
+        toolstrip_background_);
   }
 }
 
@@ -898,11 +948,17 @@ int BookmarkBarView::GetToolbarOverlap() {
 void BookmarkBarView::AnimationProgressed(const Animation* animation) {
   if (browser_)
     browser_->ToolbarSizeChanged(true);
+
+  // Clear the toolstrip background so that we recreate it next time around the
+  // paint loop.
+  toolstrip_background_.reset();
 }
 
 void BookmarkBarView::AnimationEnded(const Animation* animation) {
   if (browser_)
     browser_->ToolbarSizeChanged(false);
+
+  toolstrip_background_.reset();
   SchedulePaint();
 }
 
@@ -1379,6 +1435,7 @@ bool BookmarkBarView::AddExtensionToolstrips(const ExtensionList* extensions) {
                                  (*extension)->GetResourceURL(*toolstrip),
                                  browser_);
       int index = GetBookmarkButtonCount() + num_extension_toolstrips_;
+      view->view()->SetBackground(toolstrip_background_);
       AddChildView(index, view);
       added_toolstrip = true;
       ++num_extension_toolstrips_;