Move SkDrawLooper implementation to its own file.

src/core/SkDrawLooper.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkDrawLooper.h"
+#include "SkCanvas.h"
+#include "SkMatrix.h"
+#include "SkPaint.h"
+#include "SkRect.h"
+
+SK_DEFINE_INST_COUNT(SkDrawLooper)
+
+bool SkDrawLooper::canComputeFastBounds(const SkPaint& paint) {
+    SkCanvas canvas;
+
+    this->init(&canvas);
+    for (;;) {
+        SkPaint p(paint);
+        if (this->next(&canvas, &p)) {
+            p.setLooper(NULL);
+            if (!p.canComputeFastBounds()) {
+                return false;
+            }
+        } else {
+            break;
+        }
+    }
+    return true;
+}
+
+void SkDrawLooper::computeFastBounds(const SkPaint& paint, const SkRect& src,
+                                     SkRect* dst) {
+    SkCanvas canvas;
+
+    this->init(&canvas);
+    for (bool firstTime = true;; firstTime = false) {
+        SkPaint p(paint);
+        if (this->next(&canvas, &p)) {
+            SkRect r(src);
+
+            p.setLooper(NULL);
+            p.computeFastBounds(r, &r);
+            canvas.getTotalMatrix().mapRect(&r);
+
+            if (firstTime) {
+                *dst = r;
+            } else {
+                dst->join(r);
+            }
+        } else {
+            break;
+        }
+    }
+}