DevTools: expose last composited frame metadata on RenderWidgetHostViewPort.

content/browser/devtools/renderer_overrides_handler.cc

Index: content/browser/devtools/renderer_overrides_handler.cc
diff --git a/content/browser/devtools/renderer_overrides_handler.cc b/content/browser/devtools/renderer_overrides_handler.cc
index 3e9ffc3c203f244933567f35ed4f117cf6adc0d2..36f54929193f615a019ad9784626ad5a51996c4f 100644
--- a/content/browser/devtools/renderer_overrides_handler.cc
+++ b/content/browser/devtools/renderer_overrides_handler.cc
@@ -12,6 +12,7 @@
 #include "base/files/file_path.h"
 #include "base/strings/string16.h"
 #include "base/values.h"
+#include "cc/output/compositor_frame_metadata.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/devtools/devtools_protocol_constants.h"
 #include "content/browser/devtools/devtools_tracing_handler.h"
@@ -170,7 +171,7 @@ void RendererOverridesHandler::OnSwapCompositorFrame() {
       base::Bind(&RendererOverridesHandler::ScreenshotCaptured,
                  weak_factory_.GetWeakPtr(),
                  scoped_refptr<DevToolsProtocol::Command>(), format, quality,
-                 scale));
+                 view_port->GetCompositorFrameMetadata()));
 }
 
 
@@ -289,7 +290,7 @@ RendererOverridesHandler::PageCaptureScreenshot(
     if (success) {
       base::DictionaryValue* result = new base::DictionaryValue();
       result->SetString(
-          devtools::Page::captureScreenshot::kResponseData, base64_data);
+          devtools::Page::kData, base64_data);
       return command->SuccessResponse(result);
     }
     return command->InternalErrorResponse("Unable to base64encode screenshot");
@@ -304,7 +305,8 @@ RendererOverridesHandler::PageCaptureScreenshot(
   view_port->CopyFromCompositingSurface(
       view_bounds, snapshot_size,
       base::Bind(&RendererOverridesHandler::ScreenshotCaptured,
-                 weak_factory_.GetWeakPtr(), command, format, quality, scale));
+                 weak_factory_.GetWeakPtr(), command, format, quality,
+                 view_port->GetCompositorFrameMetadata()));

[Sami, 2013/08/28 15:42:50]

I think reading the screenshot and the frame metadata separately is going to be
too racy and lead to problems down the road. Let's take another shot at making
the compositor give back both pieces of data atomically. WDYT?

   return command->AsyncResponsePromise();
 }
 
@@ -327,7 +329,7 @@ void RendererOverridesHandler::ScreenshotCaptured(
     scoped_refptr<DevToolsProtocol::Command> command,
     const std::string& format,
     int quality,
-    double scale,
+    const cc::CompositorFrameMetadata& metadata,
     bool success,
     const SkBitmap& bitmap) {
   if (!success) {
@@ -380,14 +382,27 @@ void RendererOverridesHandler::ScreenshotCaptured(
     return;
   }
 
+  base::DictionaryValue* viewport = new base::DictionaryValue();
+  viewport->SetDouble(devtools::Page::kDeviceScaleFactor,
+                      metadata.device_scale_factor);
+  viewport->SetDouble(devtools::Page::kPageScaleFactor,
+                      metadata.page_scale_factor);
+  viewport->SetDouble(devtools::Page::kScrollLeft,
+                      metadata.root_scroll_offset.x());
+  viewport->SetDouble(devtools::Page::kScrollTop,
+                      metadata.root_scroll_offset.y());
+  viewport->SetDouble(devtools::Page::kViewportWidth,
+                      metadata.viewport_size.width());
+  viewport->SetDouble(devtools::Page::kViewportHeight,
+                      metadata.viewport_size.height());
+
   base::DictionaryValue* response = new base::DictionaryValue();
+  response->SetString(devtools::Page::kData, base_64_data);
+  response->Set(devtools::Page::kViewport, viewport);
+
   if (command) {
-    response->SetString(
-        devtools::Page::captureScreenshot::kResponseData, base_64_data);
     SendAsyncResponse(command->SuccessResponse(response));
   } else {
-    response->SetString(
-        devtools::Page::screencastFrame::kResponseData, base_64_data);
     SendNotification(devtools::Page::screencastFrame::kName, response);
   }
 }