Blink/V8 serialization: Remove ToWireBytes from SerializedScriptValue.

After the removal of byte-swapping in V8 value serialization,
SerializedScriptValue::ToWireBytes() is strictly worse than
GetWireData(), as it creates a copy of the serialized value bytes.
Removing it makes copying obvious in the callers, so it can be removed
where that results in a performance improvement.

Bug: 
Change-Id: I2c299ac4baa89ba3d33210ce64762730390c4952
Reviewed-on: https://chromium-review.googlesource.com/804902Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521423}

third_party/WebKit/Source/bindings/core/v8/serialization/SerializedScriptValue.cpp

@@ -298,19 +298,6 @@ String SerializedScriptValue::ToWireString() const {
   return wire_string;
 }
 
-void SerializedScriptValue::ToWireBytes(Vector<char>& result) const {
-  DCHECK(result.IsEmpty());
-
-  size_t result_size = (data_buffer_size_ + 1) & ~1;
-  result.resize(result_size);
-  memcpy(result.data(), data_buffer_.get(), data_buffer_size_);
-
-  if (result_size > data_buffer_size_) {
-    DCHECK_EQ(result_size, data_buffer_size_ + 1);
-    result[data_buffer_size_] = 0;
-  }
-}
-
 SerializedScriptValue::ImageBitmapContentsArray
 SerializedScriptValue::TransferImageBitmapContents(
     v8::Isolate* isolate,

third_party/WebKit/Source/bindings/core/v8/serialization/SerializedScriptValue.h

@@ -146,7 +146,6 @@ class CORE_EXPORT SerializedScriptValue
   static scoped_refptr<SerializedScriptValue> NullValue();
 
   String ToWireString() const;
-  void ToWireBytes(Vector<char>&) const;
 
   StringView GetWireData() const {
     return StringView(data_buffer_.get(), data_buffer_size_);

third_party/WebKit/Source/bindings/core/v8/serialization/SerializedScriptValueTest.cpp

@@ -12,6 +12,7 @@
 #include "bindings/core/v8/serialization/SerializedScriptValueFactory.h"
 #include "core/fileapi/File.h"
 #include "platform/testing/UnitTestHelpers.h"
+#include "platform/wtf/text/StringView.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
@@ -25,11 +26,13 @@ TEST(SerializedScriptValueTest, WireFormatRoundTrip) {
           scope.GetIsolate(), v8OriginalTrue,
           SerializedScriptValue::SerializeOptions(), ASSERT_NO_EXCEPTION);
 
-  Vector<char> wireData;
-  sourceSerializedScriptValue->ToWireBytes(wireData);
+  StringView wire_data = sourceSerializedScriptValue->GetWireData();
+  DCHECK(wire_data.Is8Bit());
 
   scoped_refptr<SerializedScriptValue> serializedScriptValue =
-      SerializedScriptValue::Create(wireData.data(), wireData.size());
+      SerializedScriptValue::Create(
+          reinterpret_cast<const char*>(wire_data.Characters8()),
+          wire_data.length());
   v8::Local<v8::Value> deserialized =
       serializedScriptValue->Deserialize(scope.GetIsolate());
   EXPECT_TRUE(deserialized->IsTrue());

third_party/WebKit/Source/bindings/modules/v8/V8BindingForModulesTest.cpp

@@ -37,6 +37,7 @@
 #include "modules/indexeddb/IDBValue.h"
 #include "platform/SharedBuffer.h"
 #include "platform/bindings/V8PerIsolateData.h"
+#include "platform/wtf/text/StringView.h"
 #include "public/platform/WebBlobInfo.h"
 #include "public/platform/WebData.h"
 #include "public/platform/WebString.h"
@@ -147,7 +148,10 @@ void SerializeV8Value(v8::Local<v8::Value> value,
   scoped_refptr<SerializedScriptValue> serialized_value =
       SerializedScriptValue::Serialize(isolate, value, options,
                                        non_throwable_exception_state);
-  serialized_value->ToWireBytes(*wire_bytes);
+  StringView ssv_wire_data = serialized_value->GetWireData();
+  DCHECK(ssv_wire_data.Is8Bit());
+  DCHECK(wire_bytes->IsEmpty());
+  wire_bytes->Append(ssv_wire_data.Characters8(), ssv_wire_data.length());
 
   // Sanity check that the serialization header has not changed, as the tests
   // that use this method rely on the header format.

third_party/WebKit/Source/modules/notifications/NotificationData.cpp

@@ -12,6 +12,7 @@
 #include "modules/notifications/NotificationOptions.h"
 #include "modules/vibration/VibrationController.h"
 #include "platform/wtf/Time.h"
+#include "platform/wtf/text/StringView.h"
 #include "public/platform/WebURL.h"
 
 namespace blink {
@@ -94,8 +95,11 @@ WebNotificationData CreateWebNotificationData(
     if (exception_state.HadException())
       return WebNotificationData();
 
+    StringView ssv_wire_data = serialized_script_value->GetWireData();
+    DCHECK(ssv_wire_data.Is8Bit());
     Vector<char> serialized_data;
-    serialized_script_value->ToWireBytes(serialized_data);
+    serialized_data.ReserveInitialCapacity(ssv_wire_data.length());
+    serialized_data.Append(ssv_wire_data.Characters8(), ssv_wire_data.length());
 
     web_data.data = serialized_data;
   }