Blimp: add packet-level DEFLATE compression using zlib.

blimp/net/test_common.h

Index: blimp/net/test_common.h
diff --git a/blimp/net/test_common.h b/blimp/net/test_common.h
index e86944b49b45c00427f2f0b7ee9f5db2f86e3d9e..479f2dcaef6ee23248b21aee61013b6f761b7653 100644
--- a/blimp/net/test_common.h
+++ b/blimp/net/test_common.h
@@ -70,9 +70,10 @@ ACTION_TEMPLATE(FillBufferFromString,
   memcpy(testing::get<buf_idx>(args)->data(), str.data(), str.size());
 }
 
-// Returns true if |buf| has a prefix of |str|.
-// Behavior is undefined if len(buf) < len(str).
-bool BufferStartsWith(net::GrowableIOBuffer* buf, const std::string& str);
+// Returns true if |buf| is prefixed by |str|.
+bool BufferStartsWith(net::GrowableIOBuffer* buf,
+                      size_t buf_size,
+                      const std::string& str);
 
 // GMock action that writes data from a BlimpMessage to a GrowableIOBuffer.
 // Advances the buffer's |offset| to the end of the message.