Revert of Make DOMWrapperWorld::current() return a reference instead of a pointer

Revert of Make DOMWrapperWorld::current() return a reference instead of a pointer (https://codereview.chromium.org/209713003/)

Also reverting dependent patch https://codereview.chromium.org/213543004

Reason for revert:
Likely to have caused memory leaks:
http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%2BLSan%20Tests%20%282%29/builds/989/steps/browser_tests/logs/stdio#failure1

(1)
Direct leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x4b50d1 in operator new(unsigned long) /usr/local/google/home/hwennborg/chromium/src/third_party/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:62
    #1 0x9bdfd8a in WebCore::V8PerContextDataHolder::install(v8::Handle<v8::Context>, WTF::PassRefPtr<WebCore::DOMWrapperWorld>) third_party/WebKit/Source/bindings/v8/V8PerContextData.cpp:56
    #2 0x9bdfa06 in WebCore::V8PerContextData::V8PerContextData(v8::Handle<v8::Context>, WTF::PassRefPtr<WebCore::DOMWrapperWorld>) third_party/WebKit/Source/bindings/v8/V8PerContextData.cpp:108
    #3 0x9bc1afd in WebCore::V8PerContextData::create(v8::Handle<v8::Context>, WTF::PassRefPtr<WebCore::DOMWrapperWorld>) third_party/WebKit/Source/bindings/v8/V8PerContextData.h:66:16
    #4 0x9be64fc in WebCore::V8PerIsolateData::ensureDomInJSContext() third_party/WebKit/Source/bindings/v8/V8PerIsolateData.cpp:132

(2)
Indirect leak of 40 byte(s) in 1 object(s) allocated from:
    #0 0x4b50d1 in operator new(unsigned long) /usr/local/google/home/hwennborg/chromium/src/third_party/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:62
    #1 0x9b2ee18 in operator new third_party/WebKit/Source/bindings/v8/DOMWrapperWorld.cpp:59:22
    #2 0x9b2ee18 in WebCore::DOMWrapperWorld::create(int, int) third_party/WebKit/Source/bindings/v8/DOMWrapperWorld.cpp:53
    #3 0x9be64e7 in WebCore::V8PerIsolateData::ensureDomInJSContext() third_party/WebKit/Source/bindings/v8/V8PerIsolateData.cpp:132
 
(3)
Indirect leak of 24 byte(s) in 1 object(s) allocated from:
    #0 0x4b46c1 in __interceptor_malloc /usr/local/google/home/hwennborg/chromium/src/third_party/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:75
    #1 0x62caf0a in partitionAllocGenericFlags third_party/WebKit/Source/wtf/PartitionAlloc.h:533
    #2 0x62caf0a in partitionAllocGeneric third_party/WebKit/Source/wtf/PartitionAlloc.h:549
    #3 0x62caf0a in WTF::fastMalloc(unsigned long) third_party/WebKit/Source/wtf/FastMalloc.cpp:125
    #4 0x9b2ed61 in operator new third_party/WebKit/Source/wtf/RefCounted.h:175
    #5 0x9b2ed61 in WebCore::DOMWrapperWorld::create(int, int) third_party/WebKit/Source/bindings/v8/DOMWrapperWorld.cpp:53

Original issue's description:
> Make DOMWrapperWorld::current() return a reference instead of a pointer
> 
> Now that it's guaranteed that DOMWrapperWorld is not 0 at any given time, we can make it a reference instead of a pointer.
> 
> BUG=341032
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170261

TBR=jochen@chromium.org,dcarney@chromium.org,abarth@chromium.org,haraken@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=341032
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170357

[enne (OOO), 2014-03-28 19:23:26]

Created Revert of Make DOMWrapperWorld::current() return a reference instead of
a pointer

[commit-bot: I haz the power, 2014-03-28 19:23:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/217053007/1

[commit-bot: I haz the power, 2014-03-28 19:23:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-28 19:23:53]

Failed to apply patch for Source/bindings/tests/results/V8TestEventTarget.h:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  can't find file to patch at input line 6
  Perhaps you used the wrong -p or --strip option?
  The text leading up to this was:
  --------------------------
  |Index: Source/bindings/tests/results/V8TestEventTarget.h
  |diff --git a/Source/bindings/tests/results/V8TestEventTarget.h
b/Source/bindings/tests/results/V8TestEventTarget.h
  |index
7871a4935faa09c8dae399c071c396166d3c1382..4aa821af8151689bd5d1c2937e964b796fac71d8
100644
  |--- a/Source/bindings/tests/results/V8TestEventTarget.h
  |+++ b/Source/bindings/tests/results/V8TestEventTarget.h
  --------------------------
  No file to patch.  Skipping patch.
  1 out of 1 hunk ignored

Patch:       Source/bindings/tests/results/V8TestEventTarget.h
Index: Source/bindings/tests/results/V8TestEventTarget.h
diff --git a/Source/bindings/tests/results/V8TestEventTarget.h
b/Source/bindings/tests/results/V8TestEventTarget.h
index
7871a4935faa09c8dae399c071c396166d3c1382..4aa821af8151689bd5d1c2937e964b796fac71d8
100644
--- a/Source/bindings/tests/results/V8TestEventTarget.h
+++ b/Source/bindings/tests/results/V8TestEventTarget.h
@@ -81,7 +81,7 @@
 template<typename CallbackInfo>
 inline void v8SetReturnValueForMainWorld(const CallbackInfo& callbackInfo,
TestEventTarget* impl)
 {
-    ASSERT(DOMWrapperWorld::current(callbackInfo.GetIsolate()).isMainWorld());
+    ASSERT(DOMWrapperWorld::current(callbackInfo.GetIsolate())->isMainWorld());
     if (UNLIKELY(!impl)) {
         v8SetReturnValueNull(callbackInfo);
         return;

[enne (OOO), 2014-03-28 19:39:22]

The CQ bit was checked by enne@chromium.org

[commit-bot: I haz the power, 2014-03-28 19:39:26]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/217053007/23

[commit-bot: I haz the power, 2014-03-28 19:41:54]

Change committed as 170357