Rename getWebView() to getWebViewClassic

Interdepends on https://android-git.corp.google.com/g/170037
Tidys up a TODO from my webview proxy patch.
This allows me to re-introduce getWebView(), but now returning the
actual WebView instance which is needed by my upcoming change to WebKit
linked above.
Also moves sendPluginDrawMsg() to WebViewCore for convenience in the
MediaTexture code that calls this.

Change-Id: I57b72504a792de58d15f386abf4a9d821449ab0a
diff --git a/core/java/android/webkit/HTML5VideoViewProxy.java b/core/java/android/webkit/HTML5VideoViewProxy.java
index 40c3778..5fa4bad 100644
--- a/core/java/android/webkit/HTML5VideoViewProxy.java
+++ b/core/java/android/webkit/HTML5VideoViewProxy.java
@@ -724,7 +724,7 @@
      * @return a new HTML5VideoViewProxy object.
      */
     public static HTML5VideoViewProxy getInstance(WebViewCore webViewCore, int nativePtr) {
-        return new HTML5VideoViewProxy(webViewCore.getWebView(), nativePtr);
+        return new HTML5VideoViewProxy(webViewCore.getWebViewClassic(), nativePtr);
     }
 
     /* package */ WebViewClassic getWebView() {