Implementation of device metrics emulation in render view.

content/renderer/devtools/devtools_agent.cc

Index: content/renderer/devtools/devtools_agent.cc
diff --git a/content/renderer/devtools/devtools_agent.cc b/content/renderer/devtools/devtools_agent.cc
index 635acc18641098000005084b573e00275d3cb652..5f26681556c75fbdad97cbc841051a746639d224 100644
--- a/content/renderer/devtools/devtools_agent.cc
+++ b/content/renderer/devtools/devtools_agent.cc
@@ -22,6 +22,7 @@
 #include "third_party/WebKit/public/web/WebConsoleMessage.h"
 #include "third_party/WebKit/public/web/WebDevToolsAgent.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
+#include "third_party/WebKit/public/web/WebSettings.h"
 #include "third_party/WebKit/public/web/WebView.h"
 
 #if defined(USE_TCMALLOC)
@@ -144,6 +145,19 @@ void DevToolsAgent::setTraceEventCallback(TraceEventCallback cb) {
   }
 }
 
+void DevToolsAgent::emulateDevice(
+    bool enabled,
+    const WebKit::WebSize& device_size,
+    const WebKit::WebRect& view_rect,
+    float device_scale_factor,
+    bool fit_to_view) {
+  RenderViewImpl* impl = static_cast<RenderViewImpl*>(render_view());
+  if (enabled && impl->webview())
+    impl->webview()->settings()->setForceCompositingMode(true);
+  impl->EmulateScreenMetrics(enabled, gfx::Size(device_size),
+      gfx::Rect(view_rect), device_scale_factor, fit_to_view);
+}
+
 #if defined(USE_TCMALLOC) && !defined(OS_WIN)
 static void AllocationVisitor(void* data, const void* ptr) {
     typedef WebKit::WebDevToolsAgentClient::AllocatedObjectVisitor Visitor;