Manage imagecache ram budget

This code was lifted from the browser, and is now global since java clients may
also use this cache for decoded images

core/jni/AndroidRuntime.cpp

@@ -30,6 +30,7 @@
 
 #include <SkGraphics.h>
 #include <SkImageDecoder.h>
+#include <SkImageRef_GlobalPool.h>
 
 #include "jni.h"
 #include "JNIHelp.h"
@@ -228,6 +229,13 @@ AndroidRuntime::AndroidRuntime()
     // this sets our preference for 16bit images during decode
     // in case the src is opaque and 24bit
     SkImageDecoder::SetDeviceConfig(SkBitmap::kRGB_565_Config);
+    // This cache is shared between browser native images, and java "purgeable"
+    // bitmaps. This globalpool is for images that do not either use the java
+    // heap, or are not backed by ashmem. See BitmapFactory.cpp for the key
+    // java call site.
+    SkImageRef_GlobalPool::SetRAMBudget(512 * 1024);
+    // There is also a global font cache, but its budget is specified in code
+    // see SkFontHost_android.cpp
 
     // Pre-allocate enough space to hold a fair number of options.
     mOptions.setCapacity(20);