Fix dictionary look-up for highlighted text in Mac.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index fa22008815a79b8747088da8dfaeb84b2c7bd229..43458dd6ce7e78419a23b5f7dfcb221b1b48cc5e 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -2357,14 +2357,34 @@ void RenderWidgetHostViewMac::OnDisplayMetricsChanged(
 
 - (void)showLookUpDictionaryOverlayFromRange:(NSRange)range
                                   targetView:(NSView*)targetView {
+  RenderWidgetHostImpl* widgetHost = renderWidgetHostView_->render_widget_host_;
+  if (!widgetHost || !widgetHost->delegate())
+    return;
+  widgetHost = widgetHost->delegate()->GetFocusedRenderWidgetHost(widgetHost);
+
+  if (!widgetHost)
+    return;
+
+  // TODO(ekaramad): The position reported by the renderer is with respect to
+  // |widgetHost|'s coordinate space with y-axis inverted to conform to AppKit
+  // coordinate system. The point will need to be transformed into root view's
+  // coordinate system (RenderWidgetHostViewMac in this case). However, since
+  // the callback is invoked on IO thread it will require some thread hopping to
+  // do so. For this reason, for now, we accept this non-ideal way of fixing the
+  // point offset manually from the view bounds. This should be revisited when
+  // fixing issues in TextInputClientMac (https://crbug.com/643233).
+  gfx::Rect root_box = renderWidgetHostView_->GetViewBounds();

[EhsanK, 2016/09/29 18:20:35]

The logic is almost identical to showLookupDictionaryOverlayAtPoint except that
we already know the widget to
talk to is the focused one (as opposed to the one at the specific cursor
position).

[Charlie Reis, 2016/09/30 23:00:55]

Will we be able to resolve these TODOs soon?  I'm not thrilled to have this much
workaround code duplicated (with a possible risk of needing it in more places).

[EhsanK, 2016/10/06 19:36:09]

This one unfortunately might need a major reworking of TextInputClientMac; which
is a good thing to do IMO. I will try to do this in very near future.

+  gfx::Rect view_box = widgetHost->GetView()->GetViewBounds();
+
   TextInputClientMac::GetInstance()->GetStringFromRange(
-      renderWidgetHostView_->render_widget_host_, range,
-      ^(NSAttributedString* string, NSPoint baselinePoint) {
+      widgetHost, range, ^(NSAttributedString* string, NSPoint baselinePoint) {
+        baselinePoint.x += view_box.origin().x() - root_box.origin().x();
+        baselinePoint.y +=
+            root_box.bottom_left().y() - view_box.bottom_left().y();
         [self showLookUpDictionaryOverlayInternal:string
                                     baselinePoint:baselinePoint
                                        targetView:targetView];
-      }
-  );
+      });
 }
 
 - (void)showLookUpDictionaryOverlayAtPoint:(NSPoint)point {