Ensure memory mapped chunk size is aligned with the FencedAllocator.

gpu/command_buffer/client/gles2_implementation.cc

Index: gpu/command_buffer/client/gles2_implementation.cc
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 75d616a9b2eb44f41dbaf75a8fb5077a4b72f307..7f49bd2f61f1d5e5c96eb4bcddb759db8d91fc6c 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -18,6 +18,7 @@
 #include <sstream>
 #include <string>
 #include "base/atomic_sequence_num.h"
+#include "base/bits.h"
 #include "base/compiler_specific.h"
 #include "base/numerics/safe_math.h"
 #include "base/strings/string_split.h"
@@ -219,6 +220,8 @@ bool GLES2Implementation::Initialize(
   if (mapped_memory_limit != SharedMemoryLimits::kNoLimit) {
     // Use smaller chunks if the client is very memory conscientious.
     chunk_size = std::min(mapped_memory_limit / 4, chunk_size);
+    chunk_size = base::bits::Align(chunk_size,
+                                   FencedAllocator::kAllocAlignment);
   }
   mapped_memory_->set_chunk_size_multiple(chunk_size);