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

content/browser/renderer_host/render_widget_host_view_android.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
 
 #include <android/bitmap.h>
 
 #include "base/android/build_info.h"
 #include "base/basictypes.h"
@@ skipping 70 matching lines @@
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/screen.h"
 #include "ui/touch_selection/touch_selection_controller.h"
 
 namespace content {
 
 namespace {
 
 const int kUndefinedOutputSurfaceId = -1;
 
-// Used to accomodate finite precision when comparing scaled viewport and
-// content widths. While this value may seem large, width=device-width on an N7
-// V1 saw errors of ~0.065 between computed window and content widths.
-const float kMobileViewportWidthEpsilon = 0.15f;
-
 static const char kAsyncReadBackString[] = "Compositing.CopyFromSurfaceTime";
 
 // Sends an acknowledgement to the renderer of a processed IME event.
 void SendImeEventAck(RenderWidgetHostImpl* host) {
   host->Send(new ViewMsg_ImeEventAck(host->GetRoutingID()));
 }
 
 class GLHelperHolder
     : public blink::WebGraphicsContext3D::WebGraphicsContextLostCallback {
  public:
@@ skipping 180 matching lines @@
 
 ui::GestureProvider::Config CreateGestureProviderConfig() {
   ui::GestureProvider::Config config = ui::GetGestureProviderConfig(
       ui::GestureProviderConfigType::CURRENT_PLATFORM);
   config.disable_click_delay =
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableClickDelay);
   return config;
 }
 
-bool HasFixedPageScale(const cc::CompositorFrameMetadata& frame_metadata) {
-  return frame_metadata.min_page_scale_factor ==
-         frame_metadata.max_page_scale_factor;
-}
-
-bool HasMobileViewport(const cc::CompositorFrameMetadata& frame_metadata) {
-  float window_width_dip =
-      frame_metadata.page_scale_factor *
-          frame_metadata.scrollable_viewport_size.width();
-  float content_width_css = frame_metadata.root_layer_size.width();
-  return content_width_css <= window_width_dip + kMobileViewportWidthEpsilon;
-}
-
 }  // anonymous namespace
 
 ReadbackRequest::ReadbackRequest(float scale,
                                  SkColorType color_type,
                                  gfx::Rect src_subrect,
                                  ReadbackRequestCallback& result_callback)
     : scale_(scale),
       color_type_(color_type),
       src_subrect_(src_subrect),
       result_callback_(result_callback) {
@@ skipping 1006 matching lines @@
   SkCanvas canvas(bitmap);
   canvas.scale(
       (float)output_width / (float)input_size_in_pixel.width(),
       (float)output_height / (float)input_size_in_pixel.height());
   compositor->DemandDrawSw(&canvas);
   callback.Run(bitmap, READBACK_SUCCESS);
 }
 
 void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
     const cc::CompositorFrameMetadata& frame_metadata) {
-
-  // Disable double tap zoom for pages that have a width=device-width or
-  // narrower viewport (indicating that this is a mobile-optimized or responsive
-  // web design, so text will be legible without zooming). Also disable
-  // double tap and pinch for pages that prevent zooming in or out.
-  bool has_mobile_viewport = HasMobileViewport(frame_metadata);
-  bool has_fixed_page_scale = HasFixedPageScale(frame_metadata);
   gesture_provider_.SetDoubleTapSupportForPageEnabled(
-      !has_fixed_page_scale && !has_mobile_viewport);
+      IsMobileOptimizedFrame(frame_metadata));
 
   if (!content_view_core_)
     return;
 
   if (overscroll_controller_)
     overscroll_controller_->OnFrameMetadataUpdated(frame_metadata);
 
   if (selection_controller_) {
     selection_controller_->OnSelectionBoundsChanged(
         ui::SelectionBound(frame_metadata.selection_start),
@@ skipping 586 matching lines @@
   results->orientationAngle = display.RotationAsDegree();
   results->orientationType =
       RenderWidgetHostViewBase::GetOrientationTypeForMobile(display);
   gfx::DeviceDisplayInfo info;
   results->depth = info.GetBitsPerPixel();
   results->depthPerComponent = info.GetBitsPerComponent();
   results->isMonochrome = (results->depthPerComponent == 0);
 }
 
 } // namespace content