Revert part of r508, it may have broken webkit-release-playback.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@514 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 10 deletions

diff --git a/base/pickle.cc b/base/pickle.cc
index 356d5df..0fb1d9c 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -309,21 +309,20 @@ char* Pickle::BeginWriteData(int length) {
   return data_ptr;
 }
 
-void Pickle::TrimWriteData(int new_length) {
+void Pickle::TrimWriteData(int length) {
   DCHECK(variable_buffer_offset_ != 0);
 
-  // Fetch the the variable buffer size
-  int* cur_length = reinterpret_cast<int*>(
+  VariableLengthBuffer *buffer = reinterpret_cast<VariableLengthBuffer*>(
       reinterpret_cast<char*>(header_) + variable_buffer_offset_);
 
-  if (new_length < 0 || new_length > *cur_length) {
-    NOTREACHED() << "Invalid length in TrimWriteData.";
-    return;
-  }
+  DCHECK_GE(buffer->length, length);
 
-  // Update the payload size and variable buffer size
-  header_->payload_size -= (*cur_length - new_length);
-  *cur_length = new_length;
+  int old_length = buffer->length;
+  int trimmed_bytes = old_length - length;
+  if (trimmed_bytes > 0) {
+    header_->payload_size -= trimmed_bytes;
+    buffer->length = length;
+  }
 }
 
 bool Pickle::Resize(size_t new_capacity) {
diff --git a/base/pickle.h b/base/pickle.h
index da2a485..7c4a007 100644
--- a/base/pickle.h
+++ b/base/pickle.h
@@ -239,6 +239,12 @@ class Pickle {
   static const int kPayloadUnit;
 
  private:
+  // A buffer of variable length; used internally
+  struct VariableLengthBuffer {
+    int length;
+    char data;   // This is variable length.
+  };
+
   Header* header_;
   size_t header_size_;  // Supports extra data between header and payload.
   // Allocation size of payload (or -1 if allocation is const).