GPU: Fix NULL gpu::Buffer dereference.

GPU: Fix NULL gpu::Buffer dereference.

After refactoring buffer from POD type to pointers, we missed
two possible NULL dereferences. This patch handles these
gracefully, as well as adds some DCHECKs in other places
(where we can safely assume Buffers are not NULL).

BUG=177063, 353822, 357140
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=260717

[epennerAtGoogle, 2014-03-28 22:44:31]

Ptal. I looked through every "->size()" in my patch and managed to find one more
in pepper. I also added a DCHECK in a couple places where it took me a moment to
confirm it's okay.

[piman, 2014-03-28 22:48:28]

LGTM. Note, I have https://codereview.chromium.org/215803002 that changes this
code anyway, but let's take this since worst case it's easier to merge.

[epenner, 2014-03-28 22:55:39]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-03-28 22:56:49]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/217593004/1

[commit-bot: I haz the power, 2014-03-28 23:38:52]

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

[commit-bot: I haz the power, 2014-03-28 23:38:52]

Try jobs failed on following builders:
  tryserver.chromium on win_chromium_compile_dbg

[epenner, 2014-03-29 00:30:22]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-03-29 00:31:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/217593004/40001

[commit-bot: I haz the power, 2014-03-29 02:06:45]

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

[commit-bot: I haz the power, 2014-03-29 02:06:46]

Try jobs failed on following builders:
  tryserver.chromium on linux_chromium_chromeos_rel

[epenner, 2014-03-29 02:23:49]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-03-29 02:24:19]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/217593004/40001

[commit-bot: I haz the power, 2014-03-29 04:01:23]

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

[commit-bot: I haz the power, 2014-03-29 04:01:23]

Try jobs failed on following builders:
  tryserver.chromium on linux_chromium_chromeos_rel

[epenner, 2014-03-31 20:02:30]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-03-31 20:03:32]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/217593004/40001

[commit-bot: I haz the power, 2014-03-31 20:04:05]

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

[commit-bot: I haz the power, 2014-03-31 20:04:06]

Failed to apply patch for gpu/command_buffer/client/mapped_memory.cc:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file gpu/command_buffer/client/mapped_memory.cc
  Hunk #1 FAILED at 88.
  1 out of 1 hunk FAILED -- saving rejects to file
gpu/command_buffer/client/mapped_memory.cc.rej

Patch:       gpu/command_buffer/client/mapped_memory.cc
Index: gpu/command_buffer/client/mapped_memory.cc
diff --git a/gpu/command_buffer/client/mapped_memory.cc
b/gpu/command_buffer/client/mapped_memory.cc
index
aeab0801aa3ea6b0c93d5856d1aadc062d13db67..3b363eb95a177bbd0e02c20035a8f0a1a8901a29
100644
--- a/gpu/command_buffer/client/mapped_memory.cc
+++ b/gpu/command_buffer/client/mapped_memory.cc
@@ -88,6 +88,7 @@ void* MappedMemoryManager::Alloc(
       cmd_buf->CreateTransferBuffer(chunk_size, &id);
   if (id  < 0)
     return NULL;
+  DCHECK(shm);
   MemoryChunk* mc = new MemoryChunk(id, shm, helper_);
   allocated_memory_ += mc->GetSize();
   chunks_.push_back(mc);

[epenner, 2014-03-31 21:09:06]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-03-31 21:10:18]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/217593004/50001

[commit-bot: I haz the power, 2014-04-01 00:36:39]

Change committed as 260717