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 ff4d50fc1a755720dea34bb841a7d9e28bba64d2..8a400e7e51592edd8c77caea38e224b25c4ce06a 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -2373,14 +2373,34 @@ 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();
+  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 {