Manual merge pinch zoom from Eclair to Master.

Too many conflicts which prevent me to use git cherry-pick.
Merge based on the source diff.

WebSettings.java
https://android-git.corp.google.com/w/?p=platform/frameworks/base.git;a=commitdiff;h=5f01d7e268167c5cfb3366ce08e20a66d9b6fa6f

WebView.java (excl. drag tracker changes)
https://android-git.corp.google.com/w/?p=platform/frameworks/base.git;a=blobdiff;f=core/java/android/webkit/WebView.java;h=ab1841e140d72c22885512722cf1b75925bb8747;hp=ed1a98ae2d9321a483f6f8fa97b29b78121e94a7;hb=eclair;hpb=db08d5cd441424e4f9621aae7c2414934f781400

WebViewCore.java
https://android-git.corp.google.com/w/?p=platform/frameworks/base.git;a=blobdiff;f=core/java/android/webkit/WebViewCore.java;h=8ac915c556e3461f3c572c3a68d191ca1fecfee7;hp=a5a48527a389609e40da14ecad8c12dd8377cfaf;hb=eclair;hpb=dafc19a1406bdd554fb4629d79c8aa4d75aca363