Mozart: Fix 0x0 crashes in example views.

apps/moterm/moterm_view.cc

 // Copyright 2015 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 "apps/moterm/moterm_view.h"
 
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES
 #endif
 
@@ skipping 210 matching lines @@
 }
 
 void MotermView::OnDraw(const mojo::gfx::composition::FrameInfo& frame_info,
                         const base::TimeDelta& time_delta) {
   if (!properties())
     return;
 
   // TODO(vtl): Draw only the dirty region(s)?
   model_state_changes_.Reset();
 
+  auto update = mojo::gfx::composition::SceneUpdate::New();
+
   const mojo::Size& size = *properties()->view_layout->size;
-  mojo::RectF bounds;
-  bounds.width = size.width;
-  bounds.height = size.height;
+  if (size.width > 0 && size.height > 0) {
+    mojo::RectF bounds;
+    bounds.width = size.width;
+    bounds.height = size.height;
 
-  auto update = mojo::gfx::composition::SceneUpdate::New();
-  mojo::gfx::composition::ResourcePtr moterm_resource =
-      ganesh_renderer()->DrawCanvas(
-          size, base::Bind(&MotermView::DrawContent, base::Unretained(this)));
-  DCHECK(moterm_resource);
-  update->resources.insert(kMotermImageResourceId, moterm_resource.Pass());
+    mojo::gfx::composition::ResourcePtr moterm_resource =
+        ganesh_renderer()->DrawCanvas(
+            size, base::Bind(&MotermView::DrawContent, base::Unretained(this)));
+    DCHECK(moterm_resource);
+    update->resources.insert(kMotermImageResourceId, moterm_resource.Pass());
 
-  auto root_node = mojo::gfx::composition::Node::New();
-  root_node->hit_test_behavior = mojo::gfx::composition::HitTestBehavior::New();
-  root_node->op = mojo::gfx::composition::NodeOp::New();
-  root_node->op->set_image(mojo::gfx::composition::ImageNodeOp::New());
-  root_node->op->get_image()->content_rect = bounds.Clone();
-  root_node->op->get_image()->image_resource_id = kMotermImageResourceId;
-  update->nodes.insert(kRootNodeId, root_node.Pass());
+    auto root_node = mojo::gfx::composition::Node::New();
+    root_node->hit_test_behavior =
+        mojo::gfx::composition::HitTestBehavior::New();
+    root_node->op = mojo::gfx::composition::NodeOp::New();
+    root_node->op->set_image(mojo::gfx::composition::ImageNodeOp::New());
+    root_node->op->get_image()->content_rect = bounds.Clone();
+    root_node->op->get_image()->image_resource_id = kMotermImageResourceId;
+    update->nodes.insert(kRootNodeId, root_node.Pass());
+  } else {
+    auto root_node = mojo::gfx::composition::Node::New();
+    update->nodes.insert(kRootNodeId, root_node.Pass());
+  }
 
   scene()->Update(update.Pass());
 
   auto metadata = mojo::gfx::composition::SceneMetadata::New();
   metadata->version = scene_version();
   metadata->presentation_time = frame_info.presentation_time;
   scene()->Publish(metadata.Pass());
 }
 
 void MotermView::DrawContent(SkCanvas* canvas) {
@@ skipping 62 matching lines @@
 
 void MotermView::OnKeyPressed(mojo::EventPtr key_event) {
   std::string input_sequence =
       GetInputSequenceForKeyPressedEvent(*key_event, keypad_application_mode_);
   if (input_sequence.empty())
     return;
 
   if (driver_)
     driver_->SendData(input_sequence.data(), input_sequence.size());
 }