Audit use of m_client in WebFrameWidgetImpl and remove null checks.

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 170 matching lines @@
 
 void WebFrameWidgetImpl::sendResizeEventAndRepaint() {
   // FIXME: This is wrong. The FrameView is responsible sending a resizeEvent
   // as part of layout. Layout is also responsible for sending invalidations
   // to the embedder. This method and all callers may be wrong. -- eseidel.
   if (m_localRoot->frameView()) {
     // Enqueues the resize event.
     m_localRoot->frame()->document()->enqueueResizeEvent();
   }
 
-  if (m_client) {
-    if (isAcceleratedCompositingActive()) {
-      updateLayerTreeViewport();
-    } else {
-      WebRect damagedRect(0, 0, m_size.width, m_size.height);
-      m_client->didInvalidateRect(damagedRect);
-    }
+  DCHECK(m_client);
+  if (isAcceleratedCompositingActive()) {
+    updateLayerTreeViewport();
+  } else {
+    WebRect damagedRect(0, 0, m_size.width, m_size.height);
+    m_client->didInvalidateRect(damagedRect);
   }
 }
 
 void WebFrameWidgetImpl::resizeVisualViewport(const WebSize& newSize) {
   // TODO(alexmos, kenrb): resizing behavior such as this should be changed
   // to use Page messages.  https://crbug.com/599688.
   page()->visualViewport().setSize(newSize);
   page()->visualViewport().clampToBoundaries();
 
   view()->didUpdateFullscreenSize();
@@ skipping 125 matching lines @@
   // Report the event to be NOT processed by WebKit, so that the browser can
   // handle it appropriately.
   if (ignoreInputEvents())
     return WebInputEventResult::NotHandled;
 
   // FIXME: pass event to m_localRoot's WebDevToolsAgentImpl once available.
 
   AutoReset<const WebInputEvent*> currentEventChange(&m_currentInputEvent,
                                                      &inputEvent);
 
+  DCHECK(m_client);

[dcheng, 2017/03/27 04:33:24]

(Also, I'm not sure where this DCHECK comes from; it looks like most of the
other ones are things that used to be checked as an if(). Is this just out of
caution?)

   if (m_client->isPointerLocked() &&
       WebInputEvent::isMouseEventType(inputEvent.type())) {
     pointerLockMouseEvent(inputEvent);
     return WebInputEventResult::HandledSystem;
   }
 
   if (m_mouseCaptureNode &&
       WebInputEvent::isMouseEventType(inputEvent.type())) {
     TRACE_EVENT1("input", "captured mouse event", "type", inputEvent.type());
     // Save m_mouseCaptureNode since mouseCaptureLost() will clear it.
@@ skipping 63 matching lines @@
 WebInputMethodControllerImpl*
 WebFrameWidgetImpl::getActiveWebInputMethodController() const {
   return WebInputMethodControllerImpl::fromFrame(focusedLocalFrameInWidget());
 }
 
 void WebFrameWidgetImpl::scheduleAnimation() {
   if (m_layerTreeView) {
     m_layerTreeView->setNeedsBeginFrame();
     return;
   }
-  if (m_client)
-    m_client->scheduleAnimation();
+  DCHECK(m_client);
+  m_client->scheduleAnimation();
 }
 
 CompositorMutatorImpl& WebFrameWidgetImpl::mutator() {
   if (!m_mutator) {
     std::unique_ptr<CompositorMutatorClient> mutatorClient =
         CompositorMutatorImpl::createClient();
     m_mutator = static_cast<CompositorMutatorImpl*>(mutatorClient->mutator());
     m_layerTreeView->setMutatorClient(std::move(mutatorClient));
   }
 
@@ skipping 386 matching lines @@
 }
 
 WebInputEventResult WebFrameWidgetImpl::handleMouseWheel(
     LocalFrame& mainFrame,
     const WebMouseWheelEvent& event) {
   return PageWidgetEventHandler::handleMouseWheel(mainFrame, event);
 }
 
 WebInputEventResult WebFrameWidgetImpl::handleGestureEvent(
     const WebGestureEvent& event) {
+  DCHECK(m_client);

[dcheng, 2017/03/27 04:33:24]

Ditto.

   WebInputEventResult eventResult = WebInputEventResult::NotHandled;
   bool eventCancelled = false;
   switch (event.type()) {
     case WebInputEvent::GestureScrollBegin:
     case WebInputEvent::GestureScrollEnd:
     case WebInputEvent::GestureScrollUpdate:
     case WebInputEvent::GestureTap:
     case WebInputEvent::GestureTapUnconfirmed:
     case WebInputEvent::GestureTapDown:
     case WebInputEvent::GestureShowPress:
@@ skipping 139 matching lines @@
     return nullptr;
 
   Document* document = frame->document();
   if (!document)
     return nullptr;
 
   return document->focusedElement();
 }
 
 void WebFrameWidgetImpl::initializeLayerTreeView() {
-  if (m_client) {
-    DCHECK(!m_mutator);
-    m_layerTreeView = m_client->initializeLayerTreeView();
-    if (m_layerTreeView && m_layerTreeView->compositorAnimationHost()) {
-      m_animationHost = WTF::makeUnique<CompositorAnimationHost>(
-          m_layerTreeView->compositorAnimationHost());
-    }
+  DCHECK(m_client);
+  DCHECK(!m_mutator);
+  m_layerTreeView = m_client->initializeLayerTreeView();
+  if (m_layerTreeView && m_layerTreeView->compositorAnimationHost()) {
+    m_animationHost = WTF::makeUnique<CompositorAnimationHost>(
+        m_layerTreeView->compositorAnimationHost());
   }
 
   if (WebDevToolsAgentImpl* devTools = m_localRoot->devToolsAgentImpl())
     devTools->layerTreeViewChanged(m_layerTreeView);
 
   page()->settings().setAcceleratedCompositingEnabled(m_layerTreeView);
   if (m_layerTreeView) {
     page()->layerTreeViewInitialized(*m_layerTreeView,
                                      m_localRoot->frame()->view());
   }
 
   // FIXME: only unittests, click to play, Android priting, and printing (for
   // headers and footers) make this assert necessary. We should make them not
   // hit this code and then delete allowsBrokenNullLayerTreeView.
-  DCHECK(m_layerTreeView || !m_client ||
-         m_client->allowsBrokenNullLayerTreeView());
+  DCHECK(m_layerTreeView || m_client->allowsBrokenNullLayerTreeView());
 }
 
 void WebFrameWidgetImpl::setIsAcceleratedCompositingActive(bool active) {
   // In the middle of shutting down; don't try to spin back up a compositor.
   // FIXME: compositing startup/shutdown should be refactored so that it
   // turns on explicitly rather than lazily, which causes this awkwardness.
   if (m_layerTreeViewClosed)
     return;
 
   DCHECK(!active || m_layerTreeView);
 
   if (m_isAcceleratedCompositingActive == active)
     return;
 
-  if (!m_client)
-    return;
-
   if (active) {
     TRACE_EVENT0("blink",
                  "WebViewImpl::setIsAcceleratedCompositingActive(true)");
     m_layerTreeView->setRootLayer(*m_rootLayer);
 
     m_layerTreeView->setVisible(page()->isPageVisible());
     updateLayerTreeDeviceScaleFactor();
     updateLayerTreeBackgroundColor();
     m_layerTreeView->setHasTransparentBackground(isTransparent());
     updateLayerTreeViewport();
@@ skipping 98 matching lines @@
   return nullptr;
 }
 
 LocalFrame* WebFrameWidgetImpl::focusedLocalFrameAvailableForIme() const {
   if (!m_imeAcceptEvents)
     return nullptr;
   return focusedLocalFrameInWidget();
 }
 
 }  // namespace blink