[devtools] Support different encodings for Page.CaptureScreenshot.

content/browser/renderer_host/render_widget_host_impl.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 35 matching lines @@
 #include "ui/base/ime/text_input_mode.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/events/gesture_detection/gesture_provider_config_helper.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/native_widget_types.h"
 
 struct FrameHostMsg_HittestData_Params;
 struct ViewHostMsg_SelectionBounds_Params;
 struct ViewHostMsg_UpdateRect_Params;
 
-namespace base {
-class RefCountedBytes;
-}
-
 namespace blink {
 class WebInputEvent;
 class WebMouseEvent;
 struct WebCompositionUnderline;
 }
 
 #if defined(OS_MACOSX)
 namespace device {
 class PowerSaveBlocker;
 }  // namespace device
 #endif
 
 namespace gfx {
+class Image;
 class Range;
 }
 
 namespace content {
 
 class BrowserAccessibilityManager;
 class InputRouter;
 class MockRenderWidgetHost;
 class RenderWidgetHostOwnerDelegate;
 class SyntheticGestureController;
@@ skipping 119 matching lines @@
   void DragSourceEndedAt(const gfx::Point& client_pt,
                          const gfx::Point& screen_pt,
                          blink::WebDragOperation operation) override;
   void DragSourceSystemDragEnded() override;
   void FilterDropData(DropData* drop_data) override;
 
   // Notification that the screen info has changed.
   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;
 
   // Sets the View of this RenderWidgetHost.
   void SetView(RenderWidgetHostViewBase* view);
 
   RenderWidgetHostDelegate* delegate() const { return delegate_; }
 
   bool empty() const { return current_size_.IsEmpty(); }
@@ skipping 468 matching lines @@
   void OnUnexpectedEventAck(UnexpectedEventAckType type) override;
 
   void OnSyntheticGestureCompleted(SyntheticGesture::Result result);
 
   // Called when there is a new auto resize (using a post to avoid a stack
   // which may get in recursive loops).
   void DelayedAutoResized();
 
   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
   // 3. Grants permissions to file system files.
   // 4. Register the files with the IsolatedContext.
   void GrantFileAccessFromDropData(DropData* drop_data);
 
   // true if a renderer has once been valid. We use this flag to display a sad
   // tab only when we lose our renderer and not if a paint occurs during
   // initialization.
@@ skipping 187 matching lines @@
 #endif
 
   base::WeakPtrFactory<RenderWidgetHostImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_