[devtools] Support different encodings for Page.CaptureScreenshot.

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 8c17eef9be6970a9fd9b47198fb2d10594983947..a5a56bedef1dc2b8c69a8675f94671e8e4e37f1c 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -53,10 +53,6 @@ struct FrameHostMsg_HittestData_Params;
 struct ViewHostMsg_SelectionBounds_Params;
 struct ViewHostMsg_UpdateRect_Params;
 
-namespace base {
-class RefCountedBytes;
-}
-
 namespace blink {
 class WebInputEvent;
 class WebMouseEvent;
@@ -70,6 +66,7 @@ class PowerSaveBlocker;
 #endif
 
 namespace gfx {
+class Image;
 class Range;
 }
 
@@ -209,9 +206,11 @@ class CONTENT_EXPORT RenderWidgetHostImpl : public RenderWidgetHost,
   void NotifyScreenInfoChanged();
 
   // Forces redraw in the renderer and when the update reaches the browser
-  // grabs snapshot from the compositor. Returns PNG-encoded snapshot.
+  // grabs snapshot from the compositor. Returns a gfx::Image that is backed
+  // by an NSImage on MacOS or by an SkBitmap otherwise. The gfx::Image may be

[Avi (use Gerrit), 2017/01/09 16:57:33]

Why are we doing things differently on the Mac than otherwise?

[Eric Seckler, 2017/01/11 15:58:44]

Everywhere but on Mac, we're grabbing from cc layers (i.e. receive SkBitmaps
directly), but on Mac, we're taking the screenshot using Cocoa. The reason for
this seems to be that DevTools' Page.CaptureScreenshot is used for end-to-end
integration-testing, see earlier comments by Pavel.

To avoid unnecessary conversion from Cocoa's NSImage to an SkBitmap and then to
a jpeg/png, we're using a gfx::Image with different representations, which we
can then convert to jpeg/png directly from the respective representation.

[Avi (use Gerrit), 2017/01/11 17:09:20]

Can we have some kind of note in the code? It's also weird that we're doing
different integration testing on different platforms forcing us to have
different app code.

[Eric Seckler, 2017/01/20 09:22:12]

Added a comment here. As I understand it, Mac is sort of a special case, because
some Cocoa features actually affect how things look, whereas on the other OSes,
aura handles pretty much everything (and thus, it suffices to compare
screenshots of aura/compositor layers there).

+  // empty if the snapshot failed.
   using GetSnapshotFromBrowserCallback =
-      base::Callback<void(const unsigned char*, size_t)>;
+      base::Callback<void(const gfx::Image&)>;
   void GetSnapshotFromBrowser(const GetSnapshotFromBrowserCallback& callback);
 
   const NativeWebKeyboardEvent* GetLastKeyboardEvent() const;
@@ -700,13 +699,7 @@ class CONTENT_EXPORT RenderWidgetHostImpl : public RenderWidgetHost,
 
   void WindowSnapshotReachedScreen(int snapshot_id);
 
-  void OnSnapshotDataReceived(int snapshot_id,
-                              const unsigned char* png,
-                              size_t size);
-
-  void OnSnapshotDataReceivedAsync(
-      int snapshot_id,
-      scoped_refptr<base::RefCountedBytes> png_data);
+  void OnSnapshotReceived(int snapshot_id, const gfx::Image& image);
 
   // 1. Grants permissions to URL (if any)
   // 2. Grants permissions to filenames