Touch emulator: enables double tap support for pages similar to Chrome on Android.

content/browser/renderer_host/frame_metadata_util.h

+// Copyright (c) 2014 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_FRAME_METADATA_UTIL_H_
+#define CONTENT_BROWSER_RENDERER_HOST_FRAME_METADATA_UTIL_H_
+
+#include "content/common/content_export.h"
+
+namespace cc {
+class CompositorFrameMetadata;
+}
+
+namespace content {
+
+// Decides whether frame metadata corresponds to mobile-optimized content.
+// By default returns |false|, except for the following cases:
+// - page that has a width=device-width or narrower viewport
+//   (indicating that this is a mobile-optimized or responsive web design);
+// - page that prevents zooming in or out.
+CONTENT_EXPORT bool IsMobileOptimizedFrame(
+    const cc::CompositorFrameMetadata& frame_metadata);
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_FRAME_METADATA_UTIL_H_