DevTools: kill StringMap collection

There's no more need in StringMap as far as we use native Map
implementation.

This patch purges StringMap class and re-implements StringMultimap.

R=vsevik, apavlov, pfeldman

Review URL: https://codereview.chromium.org/673703002

git-svn-id: svn://svn.chromium.org/blink/trunk@184518 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move the v8::Isolate* parameter to the first parameter of various binding methods in third_party/WebKit/Source/bindings

This step is to move the v8::Isolate* parameter to the first parameter of various binding methods in third_party/WebKit/Source/bindings
(Ref: binding-methods changed:
v8::Handle<v8::String> v8ExternalStringSlow(StringImpl*, v8::Isolate*)
v8::Local<v8::String> createStringAndInsertIntoCache(StringImpl*, v8::Isolate*))

BUG=424446

Review URL: https://codereview.chromium.org/684803002

git-svn-id: svn://svn.chromium.org/blink/trunk@184519 bbb929c8-8fbe-4397-9dbb-9b2b20218538