Fix the failure when enabling v8 profiler or vtune profiler in chromium.

Fix the failure when enabling v8 profiler or vtune profiler in chromium.

   When enabling the v8 profiler (Using the following command parameters: --js-flags=--prof)
   or vtune profiling in chromium. it will break. This failure is introduced by this CL:
   https://codereview.chromium.org/1218863002.

   The reason is that V8 will enable the JITted code logging if --prof is set for V8. And under
   this condition, the function Logger::LogCodeObjects() will be invoked and it will trigger a
   mark-compact GC when deserializing the snapshot. This GC will use MemoryReducer to post a
   delay task by invoking V8Platform::CallDelayedOnForegroundThread() function. But at this point
   V8 isolation is still under initialization and the PerIsolationData of this isolation has not
   been created. (isolation_holder.cc:39~40 line). This leads to V8Platform::CallDelayedOnForegroundThread()
   failure because of segment fault.

   According to my understanding, I proposed the following fix. If the heap deserialization has not
   be completed, it does not post the delay task for next GC.

BUG=v8:4352
Committed: https://crrev.com/8ae236c0c4bcc7218f2f2dcf909c1410b9ce065e
Cr-Commit-Position: refs/heads/master@{#29937}

[chunyang.dai, 2015-07-30 10:14:40]

chunyang.dai@intel.com changed reviewers:
+ ulan@chromium.org

[chunyang.dai, 2015-07-30 10:14:41]

PTAL.

[ulan, 2015-07-30 10:34:09]

Thanks!

https://codereview.chromium.org/1270493002/diff/1/src/heap/heap.cc
File src/heap/heap.cc (right):

https://codereview.chromium.org/1270493002/diff/1/src/heap/heap.cc#newcode969
src/heap/heap.cc:969: memory_reducer_.NotifyMarkCompact(event);
Please guard just this line with "if (deserialization_complete_)"

[chunyang.dai, 2015-07-30 13:43:18]

updated. 

thanks.

[ulan, 2015-07-30 13:48:57]

lgtm

[chunyang.dai, 2015-07-30 13:58:07]

The CQ bit was checked by chunyang.dai@intel.com

[commit-bot: I haz the power, 2015-07-30 13:58:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1270493002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1270493002/20001

[commit-bot: I haz the power, 2015-07-30 14:30:13]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-30 14:30:54]

Patchset 2 (id:??) landed as
https://crrev.com/8ae236c0c4bcc7218f2f2dcf909c1410b9ce065e
Cr-Commit-Position: refs/heads/master@{#29937}