DevTools: generate string16-based handlers for v8_inspector.

third_party/WebKit/LayoutTests/inspector-protocol/css/css-set-media-text-expected.txt

 ==== Initial style sheet text ====
 @media screen and (min-width: 700px) and (max-device-height: 200em) {
     body {
         padding: 0;
     }
 }
 
  @media all and (orientation: portrait),
 handheld and (max-width: 700px),
 (max-resolution: 3dppx) {
@@ skipping 46 matching lines @@
  @media all and (orientation: portrait),
 handheld and (max-width: 700px),
 (max-resolution: 3dppx) {
     body {
         padding: 10px;
     }
 }
 
 
 Running test: testInvalidParameters
-Expected protocol error: Some arguments of method 'CSS.setMediaText' can't be processed (range.startLine: integer value expected)
+Expected protocol error: Invalid request (range.startLine: integer value expected)
 
 Running test: testInvalidText
 Expected protocol error: SyntaxError Selector or media text is not valid.
 
 Running test: testEditSequentially
 ==== Style sheet text ====
 @media screen {
     body {
         padding: 0;
     }
@@ skipping 35 matching lines @@
 
  @media all and (orientation: portrait),
 handheld and (max-width: 700px),
 (max-resolution: 3dppx) {
     body {
         padding: 10px;
     }
 }