Adds link disambiguation popup support to Windows.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index a54d860bc9e646cb9c5d0c9b52559e8042e2f17f..cd97c39fe691fc1b5398abd4db5cff1c1468558d 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -29,6 +29,7 @@
 #include "content/browser/renderer_host/input/synthetic_gesture_target_aura.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
+#include "content/browser/renderer_host/render_view_host_delegate_view.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/ui_events_helper.h"
@@ -1230,6 +1231,58 @@ gfx::GLSurfaceHandle RenderWidgetHostViewAura::GetCompositingSurface() {
   return ImageTransportFactory::GetInstance()->GetSharedSurfaceHandle();
 }
 
+void RenderWidgetHostViewAura::ShowDisambiguationPopup(
+    const gfx::Rect& target_rect,
+    const SkBitmap& zoomed_bitmap) {
+  // |target_rect| is provided in pixels, not DIPs. So we convert it to DIPs
+  // by scaling it by the inverse of the device scale factor.
+  gfx::RectF screen_target_rect_f(target_rect);
+  screen_target_rect_f.Scale(1.0f / current_device_scale_factor_);
+  disambiguation_target_rect_ = gfx::ToEnclosingRect(screen_target_rect_f);

[sky, 2014/09/11 14:53:43]

Won't this conversion be losing? Will it matter?

[luken, 2014/09/17 00:00:48]

Yes, it loses accuracy. No, it doesn't seem to matter to the quality of the
results.

+
+  float scale = static_cast<float>(zoomed_bitmap.width()) /
+                static_cast<float>(target_rect.width());
+  gfx::Size zoomed_size(gfx::ToCeiledSize(
+      gfx::ScaleSize(disambiguation_target_rect_.size(), scale)));
+
+  CopyFromCompositingSurface(
+      disambiguation_target_rect_,
+      zoomed_size,
+      base::Bind(&RenderWidgetHostViewAura::DisambiguationPopupRendered,

[sky, 2014/09/11 14:53:43]

How do you know by the time this is returned that the page has shifted around?

[luken, 2014/09/17 00:00:48]

I've added code to save the last_scroll_offset_ for comparison once the callback
fires. If they are different we don't render the popup.

[sky, 2014/09/19 15:19:23]

Is that really enough? Might the dom or other random things have changed
resulting in things shifting around?

[luken, 2014/09/19 19:27:41]

AFAICT we are already doing more than what this feature on Android is doing in
trying to keep these two views in sync. Blink doesn't provide any signals to the
client that we should stop showing the link disambiguation popup. Any activity
by the user outside of the bubble will dismiss it.

It is a good point that there's no step taken to update the image within the
bubble or possibly dismiss it if the DOM or other elements move around on the
content page. I'm open to suggestion here - do you have any ideas about how we
could implement this?

[sky, 2014/09/22 15:01:30]

Have you talked with any of the guys on the Android side to see if this issue
comes up much in practice?

+          base::internal::SupportsWeakPtrBase::StaticAsWeakPtr
+              <RenderWidgetHostViewAura>(this)),
+      kN32_SkColorType);
+}
+
+void RenderWidgetHostViewAura::DisambiguationPopupRendered(
+    bool success,
+    const SkBitmap& result) {
+  if (!success)
+    return;
+
+  // Use RenderViewHostDelegate to get to the WebContentsViewAura, which will
+  // actually show the delegate.
+  RenderViewHostDelegate* delegate = NULL;
+  if (host_->IsRenderView())
+    delegate = RenderViewHost::From(host_)->GetDelegate();
+  RenderViewHostDelegateView* delegate_view = NULL;
+  if (delegate)
+    delegate_view = delegate->GetDelegateView();
+  if (delegate_view)
+    delegate_view->ShowDisambiguationPopup(disambiguation_target_rect_, result);
+}
+
+void RenderWidgetHostViewAura::HideDisambiguationPopup() {
+  RenderViewHostDelegate* delegate = NULL;
+  if (host_->IsRenderView())
+    delegate = RenderViewHost::From(host_)->GetDelegate();
+  RenderViewHostDelegateView* delegate_view = NULL;
+  if (delegate)
+    delegate_view = delegate->GetDelegateView();
+  if (delegate_view)
+    delegate_view->HideDisambiguationPopup();
+}
+
 bool RenderWidgetHostViewAura::LockMouse() {
   aura::Window* root_window = window_->GetRootWindow();
   if (!root_window)
@@ -1845,6 +1898,9 @@ void RenderWidgetHostViewAura::OnMouseEvent(ui::MouseEvent* event) {
                         DismissOwnedPopups,
                         reinterpret_cast<LPARAM>(toplevel_hwnd));
     }
+    // The Disambiguation popup does not parent itself from this window, so we
+    // manually dismiss it.
+    HideDisambiguationPopup();

[sky, 2014/09/11 14:53:43]

Why is this in the ifdef? Also, it seems like the popup should take care of this
itself.

[luken, 2014/09/17 00:00:48]

I moved it outside of the ifdef. I wasn't able to figure out a way to determine
from the popup that the user had used the mouse wheel to scroll this window, and
I saw the code above that is dismissing other popups so it seemed like the right
place. Do you have any other ideas?

 #endif
     blink::WebMouseWheelEvent mouse_wheel_event =
         MakeWebMouseWheelEvent(static_cast<ui::MouseWheelEvent*>(event));