IPC pickling optimization for render passes.

base/pickle.h

Index: base/pickle.h
diff --git a/base/pickle.h b/base/pickle.h
index cb9bab98965f141b5ea9bffe264ed5cc76ba77e2..e04cf920c1f1da999be3d5c3731f418e1acf76bf 100644
--- a/base/pickle.h
+++ b/base/pickle.h
@@ -273,6 +273,11 @@ class BASE_EXPORT Pickle {
   // not been changed.
   void TrimWriteData(int length);
 
+  // Reserves space for upcoming writes when multiple writes will be made and
+  // their sizes are computed in advance. It can be significantly faster to call
+  // Reserve() before calling WriteFoo() multiple times.
+  void Reserve(size_t size);

[Tom Sepez, 2013/10/24 17:48:06]

Is |size| the additional amount of space to reserve, or the total space to
reserve?  I'd name the parameter |additional_capacity| or |new_capacity|
accordingly to match Resize() below.

[danakj, 2013/10/24 17:51:38]

Additional space, I will rename it to additional_capacity.

+
   // Payload follows after allocation of Header (header size is customizable).
   struct Header {
     uint32 payload_size;  // Specifies the size of the payload.
@@ -328,9 +333,7 @@ class BASE_EXPORT Pickle {
 
   // Resize the capacity, note that the input value should include the size of
   // the header: new_capacity = sizeof(Header) + desired_payload_capacity.
-  // A realloc() failure will cause a Resize failure... and caller should check
-  // the return result for true (i.e., successful resizing).
-  bool Resize(size_t new_capacity);
+  void Resize(size_t new_capacity);
 
   // Aligns 'i' by rounding it up to the next multiple of 'alignment'
   static size_t AlignInt(size_t i, int alignment) {