toV8Context should handle a case where WindowProxy::context() returns an empty handle.

windowProxy()->context() can return nullptr if the windowProxy() failed at initializing
the context for some reason. Thus the caller site of windowProxy()->context() need to
handle a case where the windowProxy()->context() returns an empty handle.

This CL renames WindowProxy::context() to WindowProxy::contextIfInitialized() for clarity.

BUG=571720
TEST=None. The test case reported by the clusterfuzz is too large to minimize.

Review URL: https://codereview.chromium.org/1546253003

Cr-Commit-Position: refs/heads/master@{#367498}

3 files changed, 11 insertions, 8 deletions

diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptController.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptController.cpp
index dbc24fd..eb0cc56 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptController.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptController.cpp
@@ -251,18 +251,19 @@ bool ScriptController::bindToWindowObject(LocalFrame* frame, const String& key,
 
 void ScriptController::enableEval()
 {
-    if (!m_windowProxyManager->mainWorldProxy()->isContextInitialized())
-        return;
     v8::HandleScope handleScope(isolate());
-    m_windowProxyManager->mainWorldProxy()->context()->AllowCodeGenerationFromStrings(true);
+    v8::Local<v8::Context> v8Context = m_windowProxyManager->mainWorldProxy()->contextIfInitialized();
+    if (v8Context.IsEmpty())
+        return;
+    v8Context->AllowCodeGenerationFromStrings(true);
 }
 
 void ScriptController::disableEval(const String& errorMessage)
 {
-    if (!m_windowProxyManager->mainWorldProxy()->isContextInitialized())
-        return;
     v8::HandleScope handleScope(isolate());
-    v8::Local<v8::Context> v8Context = m_windowProxyManager->mainWorldProxy()->context();
+    v8::Local<v8::Context> v8Context = m_windowProxyManager->mainWorldProxy()->contextIfInitialized();
+    if (v8Context.IsEmpty())
+        return;
     v8Context->AllowCodeGenerationFromStrings(false);
     v8Context->SetErrorMessageForCodeGenerationFromStrings(v8String(isolate(), errorMessage));
 }
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp b/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
index b4830c5f..bd44979 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
@@ -790,6 +790,8 @@ v8::Local<v8::Context> toV8Context(Frame* frame, DOMWrapperWorld& world)
     if (!frame)
         return v8::Local<v8::Context>();
     v8::Local<v8::Context> context = toV8ContextEvenIfDetached(frame, world);
+    if (context.IsEmpty())
+        return v8::Local<v8::Context>();
     ScriptState* scriptState = ScriptState::from(context);
     if (scriptState->contextIsValid()) {
         ASSERT(toFrameIfNotDetached(context) == frame);
@@ -801,7 +803,7 @@ v8::Local<v8::Context> toV8Context(Frame* frame, DOMWrapperWorld& world)
 v8::Local<v8::Context> toV8ContextEvenIfDetached(Frame* frame, DOMWrapperWorld& world)
 {
     ASSERT(frame);
-    return frame->windowProxy(world)->context();
+    return frame->windowProxy(world)->contextIfInitialized();
 }
 
 void crashIfIsolateIsDead(v8::Isolate* isolate)
diff --git a/third_party/WebKit/Source/bindings/core/v8/WindowProxy.h b/third_party/WebKit/Source/bindings/core/v8/WindowProxy.h
index c21737b..fbcb3f4 100644
--- a/third_party/WebKit/Source/bindings/core/v8/WindowProxy.h
+++ b/third_party/WebKit/Source/bindings/core/v8/WindowProxy.h
@@ -58,7 +58,7 @@ public:
     ~WindowProxy();
     DECLARE_TRACE();
 
-    v8::Local<v8::Context> context() const { return m_scriptState ? m_scriptState->context() : v8::Local<v8::Context>(); }
+    v8::Local<v8::Context> contextIfInitialized() const { return m_scriptState ? m_scriptState->context() : v8::Local<v8::Context>(); }
     ScriptState* scriptState() const { return m_scriptState.get(); }
 
     // Update document object of the frame.