Add rudimentary statistics gathering for WebKit2

Reviewed by Anders Carlsson.

WebKit2: 

* UIProcess/API/C/WKContext.cpp:
(WKContextGetStatistics):
* UIProcess/API/C/WKContextPrivate.h: Copied from WebKit2/UIProcess/API/C/WKContext.h.
* UIProcess/API/C/WKPageNamespace.cpp:
(WKPageNamespaceGetContext):
* UIProcess/API/C/WKPageNamespace.h:
* UIProcess/WebContext.cpp:
(WebKit::WebContext::getStatistics):
* UIProcess/WebContext.h:
* UIProcess/WebPageNamespace.cpp:
(WebKit::WebPageNamespace::getStatistics):
* UIProcess/WebPageNamespace.h:
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::getStatistics):
* UIProcess/WebPageProxy.h:
* UIProcess/WebProcessProxy.cpp:
(WebKit::WebProcessProxy::numberOfPages):
* UIProcess/WebProcessProxy.h:
* WebKit2.xcodeproj/project.pbxproj:
* win/WebKit2.vcproj:

WebKitTools: 

* MiniBrowser/MiniBrowser.xcodeproj/project.pbxproj:
* MiniBrowser/mac/AppDelegate.h:
* MiniBrowser/mac/AppDelegate.m:
(-[BrowserAppDelegate init]):
(-[BrowserAppDelegate newWindow:]):
(-[BrowserAppDelegate getCurrentPageNamespace]):
(-[BrowserAppDelegate _setProcessModel:]):
(-[BrowserAppDelegate showStatisticsWindow:]):
(-[BrowserAppDelegate applicationWillTerminate:]):
* MiniBrowser/mac/BrowserStatisticsWindow.xib: Added.
* MiniBrowser/mac/BrowserStatisticsWindowController.h: Added.
* MiniBrowser/mac/BrowserStatisticsWindowController.m: Added.
(-[BrowserStatisticsWindowController initWithThreadedWKContextRef:processWKContextRef:]):
(-[BrowserStatisticsWindowController dealloc]):
(-[BrowserStatisticsWindowController windowDidLoad]):
(-[BrowserStatisticsWindowController refreshStatistics:]):
* MiniBrowser/mac/BrowserWindowController.h:
* MiniBrowser/mac/English.lproj/MainMenu.xib:
* MiniBrowser/mac/MiniBrowser_Prefix.pch:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@58117 268f45cc-cd09-0410-ab3c-d52691b4dbfc