Use base::Optional for both |view_rect_| and |element_size_|

This CL allows creation of MimeHandlerViewGuest even when element size is
0x0. This is specifically important for Google slides pages where an
<embed> of size 0 is used for print previewing the page. Essentially,
we need to makes sure for such <embed>'s the guest is created (after
attaching) and embed.postMessage works fine.

Bug : 763812

Change-Id: I7ad0cd0898aee2e1b5d6b15dd9bfdcb100a8e16b
Reviewed-on: https://chromium-review.googlesource.com/667900
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Reviewed-by: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502847}

content/renderer/browser_plugin/browser_plugin.cc

@@ -263,10 +263,12 @@ void BrowserPlugin::OnGuestReady(int browser_plugin_instance_id,
                                  const viz::FrameSinkId& frame_sink_id) {
   guest_crashed_ = false;
   frame_sink_id_ = frame_sink_id;
-  gfx::Rect view_rect = view_rect_;
+  if (!view_rect_)
+    return;
+
+  gfx::Rect view_rect = *view_rect_;
   view_rect_ = gfx::Rect();
-  if (!view_rect.IsEmpty())
-    ViewRectsChanged(view_rect);
+  ViewRectsChanged(view_rect);
 }
 
 void BrowserPlugin::OnSetCursor(int browser_plugin_instance_id,
@@ -321,7 +323,8 @@ void BrowserPlugin::UpdateInternalInstanceId() {
 }
 
 void BrowserPlugin::ViewRectsChanged(const gfx::Rect& view_rect) {
-  bool rect_size_changed = view_rect_.size() != view_rect.size();
+  bool rect_size_changed =
+      !view_rect_ || view_rect_->size() != view_rect.size();
   if (rect_size_changed || !local_surface_id_.is_valid()) {
     local_surface_id_ = local_surface_id_allocator_.GenerateId();
     if (compositing_helper_ && enable_surface_synchronization_ &&
@@ -343,11 +346,11 @@ void BrowserPlugin::ViewRectsChanged(const gfx::Rect& view_rect) {
   if (attached()) {
     // Let the browser know about the updated view rect.
     BrowserPluginManager::Get()->Send(new BrowserPluginHostMsg_UpdateGeometry(
-        browser_plugin_instance_id_, view_rect_, local_surface_id_));
+        browser_plugin_instance_id_, *view_rect_, local_surface_id_));
   }
 
   if (rect_size_changed && delegate_)
-    delegate_->DidResizeElement(view_rect_.size());
+    delegate_->DidResizeElement(view_rect_->size());
 }
 
 void BrowserPlugin::UpdateGuestFocusState(blink::WebFocusType focus_type) {

content/renderer/browser_plugin/browser_plugin.h

@@ -11,6 +11,7 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "components/viz/common/surfaces/frame_sink_id.h"
 #include "components/viz/common/surfaces/local_surface_id.h"
@@ -145,7 +146,7 @@ class CONTENT_EXPORT BrowserPlugin : public blink::WebPlugin,
 
   ~BrowserPlugin() override;
 
-  gfx::Rect view_rect() const { return view_rect_; }
+  gfx::Rect view_rect() const { return view_rect_.value_or(gfx::Rect()); }
 
   void UpdateInternalInstanceId();
 
@@ -175,7 +176,7 @@ class CONTENT_EXPORT BrowserPlugin : public blink::WebPlugin,
   const int render_frame_routing_id_;
   blink::WebPluginContainer* container_;
   // The plugin's rect in css pixels.
-  gfx::Rect view_rect_;
+  base::Optional<gfx::Rect> view_rect_;
   bool guest_crashed_;
   bool plugin_focused_;
   // Tracks the visibility of the browser plugin regardless of the whole

extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc

@@ -317,7 +317,7 @@ void MimeHandlerViewContainer::OnMimeHandlerViewGuestOnLoadCompleted(
 }
 
 void MimeHandlerViewContainer::CreateMimeHandlerViewGuestIfNecessary() {
-  if (guest_created_ || element_size_.IsEmpty() || view_id_.empty())
+  if (guest_created_ || !element_size_.has_value() || view_id_.empty())
     return;
 
   // The loader has completed loading |view_id_| so we can dispose it.
@@ -334,7 +334,7 @@ void MimeHandlerViewContainer::CreateMimeHandlerViewGuestIfNecessary() {
   render_frame()->Send(
       new ExtensionsGuestViewHostMsg_CreateMimeHandlerViewGuest(
           render_frame()->GetRoutingID(), view_id_, element_instance_id(),
-          element_size_));
+          *element_size_));
 
   guest_created_ = true;
 }

extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.h

@@ -12,6 +12,7 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "components/guest_view/renderer/guest_view_container.h"
 #include "third_party/WebKit/public/web/WebAssociatedURLLoaderClient.h"
 #include "ui/gfx/geometry/size.h"
@@ -122,7 +123,7 @@ class MimeHandlerViewContainer : public guest_view::GuestViewContainer,
   bool guest_loaded_;
 
   // The size of the element.
-  gfx::Size element_size_;
+  base::Optional<gfx::Size> element_size_;
 
   base::WeakPtrFactory<MimeHandlerViewContainer> weak_factory_;