IPC pickling optimization for render passes.

Call Pickle::Reserve() for the size of the data in the shared quad
state and quad lists. This prevents the WriteFoo() invocations for
all of the quad/shared quad states from causing memory re-allocations
and moves.

This is based on https://codereview.chromium.org/34413002/ from piman@.

This is also based after https://codereview.chromium.org/30593005/ and
perf numbers (both before and after) include that CL also.

content_perftest results on linux chromeos release official build:

BEFORE
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_1_4000= 50 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_1_100000= 1888 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_4000_4000= 728 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_100000_100000= 23771 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyRenderPasses_10000_100= 24118 us

AFTER
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_1_4000= 48 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_1_100000= 1626 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_4000_4000= 460 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyQuads_100000_100000= 14771 us
*RESULT mean_frame_serialization_time: DelegatedFrame_ManyRenderPasses_10000_100= 15626 us

This gives a further ~1.5x improvement in serialization time for shared quad
states and render passes.

R=jar@chromium.org, piman@chromium.org, tsepez@chromium.org, piman
BUG=307480

Review URL: https://codereview.chromium.org/35893002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231656 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 1 deletions

diff --git a/base/pickle.cc b/base/pickle.cc
index 1d300b9..db78a4d 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -304,8 +304,18 @@ void Pickle::TrimWriteData(int new_length) {
   *cur_length = new_length;
 }
 
+void Pickle::Reserve(size_t additional_capacity) {
+  // Write at a uint32-aligned offset from the beginning of the header.
+  size_t offset = AlignInt(header_->payload_size, sizeof(uint32));
+
+  size_t new_size = offset + additional_capacity;
+  size_t needed_size = header_size_ + new_size;
+  if (needed_size > capacity_)
+    Resize(capacity_ * 2 + needed_size);
+}
+
 char* Pickle::BeginWrite(size_t length) {
-  // write at a uint32-aligned offset from the beginning of the header
+  // Write at a uint32-aligned offset from the beginning of the header.
   size_t offset = AlignInt(header_->payload_size, sizeof(uint32));
 
   size_t new_size = offset + length;