Use Minikin grapheme cluster breaking

This patch uses the Minikin implementation of grapheme cluster breaking,
which improves the behavior of left and right arrow keys for moving the
cursor. Among other things, it fixes the behavior of jumping over the
"fi" ligature in Roboto.

Part of a fix for b/15653110 Improve behavior of arrow keys in EditText

Change-Id: I80ca54c973d85c49f23b81d51a0fe07a7a853d81

core/jni/android/graphics/Paint.cpp

@@ -37,6 +37,7 @@
 #include "TextLayout.h"
 
 #ifdef USE_MINIKIN
+#include <minikin/GraphemeBreak.h>
 #include <minikin/Layout.h>
 #include "MinikinSkia.h"
 #include "MinikinUtils.h"
@@ -778,6 +779,11 @@ public:
 
     static jint doTextRunCursor(JNIEnv *env, SkPaint* paint, const jchar *text, jint start,
             jint count, jint flags, jint offset, jint opt) {
+#ifdef USE_MINIKIN
+        GraphemeBreak::MoveOpt moveOpt = GraphemeBreak::MoveOpt(opt);
+        size_t result = GraphemeBreak::getTextRunCursor(text, start, count, offset, moveOpt);
+        return static_cast<jint>(result);
+#else
         jfloat scalarArray[count];
 
         TextLayout::getTextRunAdvances(paint, text, start, count, start + count, flags,
@@ -818,6 +824,7 @@ public:
         }
 
         return pos;
+#endif
     }
 
     static jint getTextRunCursor___C(JNIEnv* env, jobject clazz, jlong paintHandle, jcharArray text,