When skia run bench cases to test performance, it will run constructors for all cases one by one, then getName to skip unnecessary cases according to command line parameters, so these constructors should be lightweight enough to avoid redundant computing. Unfortunately, some constructors contain intensive computing/rendering. They are very heavy, maybe much heavier than need-to-run bench case itself. And these redundant computation will be run every time you run bench, even you just test a single simple case. Moreover, it will mislead the real hotspot/bottleneck of the case itself. 
For example, run a lightweight case, say, region_intersectsrgn_16, the hot spots are gles operation, SuperBlitter, SkRTree... introduced by irrelevant cases' constructors. These redundant computation will mislead performance tuning. 
So we can move these intensive computation to onPreDraw() of these case. They will be executed only if this case should be run.

R=reed@google.com, robertphillips@google.com, humper@google.com, tomhudson@chromium.org

Author: yunchao.he@intel.com

Review URL: https://chromiumcodereview.appspot.com/20997003

git-svn-id: http://skia.googlecode.com/svn/trunk@10486 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/RepeatTileBench.cpp b/bench/RepeatTileBench.cpp
index 11dd6f8..348f906 100644
--- a/bench/RepeatTileBench.cpp
+++ b/bench/RepeatTileBench.cpp
@@ -17,7 +17,7 @@
     "ERROR", "a1", "a8", "index8", "565", "4444", "8888"
 };
 
-static void drawIntoBitmap(const SkBitmap& bm) {
+static void draw_into_bitmap(const SkBitmap& bm) {
     const int w = bm.width();
     const int h = bm.height();
 
@@ -36,32 +36,32 @@
     canvas.drawRect(r, p);
 }
 
-static int conv6ToByte(int x) {
+static int conv_6_to_byte(int x) {
     return x * 0xFF / 5;
 }
 
-static int convByteTo6(int x) {
+static int conv_byte_to_6(int x) {
     return x * 5 / 255;
 }
 
-static uint8_t compute666Index(SkPMColor c) {
+static uint8_t compute_666_index(SkPMColor c) {
     int r = SkGetPackedR32(c);
     int g = SkGetPackedG32(c);
     int b = SkGetPackedB32(c);
 
-    return convByteTo6(r) * 36 + convByteTo6(g) * 6 + convByteTo6(b);
+    return conv_byte_to_6(r) * 36 + conv_byte_to_6(g) * 6 + conv_byte_to_6(b);
 }
 
-static void convertToIndex666(const SkBitmap& src, SkBitmap* dst) {
+static void convert_to_index666(const SkBitmap& src, SkBitmap* dst) {
     SkColorTable* ctable = new SkColorTable(216);
     SkPMColor* colors = ctable->lockColors();
     // rrr ggg bbb
     for (int r = 0; r < 6; r++) {
-        int rr = conv6ToByte(r);
+        int rr = conv_6_to_byte(r);
         for (int g = 0; g < 6; g++) {
-            int gg = conv6ToByte(g);
+            int gg = conv_6_to_byte(g);
             for (int b = 0; b < 6; b++) {
-                int bb = conv6ToByte(b);
+                int bb = conv_6_to_byte(b);
                 *colors++ = SkPreMultiplyARGB(0xFF, rr, gg, bb);
             }
         }
@@ -78,51 +78,60 @@
         const SkPMColor* srcP = src.getAddr32(0, y);
         uint8_t* dstP = dst->getAddr8(0, y);
         for (int x = src.width() - 1; x >= 0; --x) {
-            *dstP++ = compute666Index(*srcP++);
+            *dstP++ = compute_666_index(*srcP++);
         }
     }
 }
 
 class RepeatTileBench : public SkBenchmark {
-    SkPaint     fPaint;
-    SkString    fName;
+    SkPaint          fPaint;
+    SkString         fName;
+    SkBitmap         fBitmap;
+    bool             fIsOpaque;
+    SkBitmap::Config fConfig;
     enum { N = SkBENCHLOOP(20) };
 public:
     RepeatTileBench(void* param, SkBitmap::Config c, bool isOpaque = false) : INHERITED(param) {
         const int w = 50;
         const int h = 50;
-        SkBitmap bm;
+        fConfig = c;
+        fIsOpaque = isOpaque;
 
-        if (SkBitmap::kIndex8_Config == c) {
-            bm.setConfig(SkBitmap::kARGB_8888_Config, w, h);
+        if (SkBitmap::kIndex8_Config == fConfig) {
+            fBitmap.setConfig(SkBitmap::kARGB_8888_Config, w, h);
         } else {
-            bm.setConfig(c, w, h);
+            fBitmap.setConfig(fConfig, w, h);
         }
-        bm.allocPixels();
-        bm.eraseColor(isOpaque ? SK_ColorWHITE : 0);
-        bm.setIsOpaque(isOpaque);
-
-        drawIntoBitmap(bm);
-
-        if (SkBitmap::kIndex8_Config == c) {
-            SkBitmap tmp;
-            convertToIndex666(bm, &tmp);
-            bm = tmp;
-        }
-
-        SkShader* s = SkShader::CreateBitmapShader(bm,
-                                                   SkShader::kRepeat_TileMode,
-                                                   SkShader::kRepeat_TileMode);
-        fPaint.setShader(s)->unref();
-        fName.printf("repeatTile_%s_%c", gConfigName[bm.config()], isOpaque ? 'X' : 'A');
+        fName.printf("repeatTile_%s_%c",
+                     gConfigName[fBitmap.config()], isOpaque ? 'X' : 'A');
     }
 
 protected:
-    virtual const char* onGetName() {
+    virtual const char* onGetName() SK_OVERRIDE {
         return fName.c_str();
     }
 
-    virtual void onDraw(SkCanvas* canvas) {
+    virtual void onPreDraw() SK_OVERRIDE {
+        fBitmap.allocPixels();
+        fBitmap.eraseColor(fIsOpaque ? SK_ColorWHITE : 0);
+        fBitmap.setIsOpaque(fIsOpaque);
+
+        draw_into_bitmap(fBitmap);
+
+        if (SkBitmap::kIndex8_Config == fConfig) {
+            SkBitmap tmp;
+            convert_to_index666(fBitmap, &tmp);
+            fBitmap = tmp;
+        }
+
+        SkShader* s = SkShader::CreateBitmapShader(fBitmap,
+                                                   SkShader::kRepeat_TileMode,
+                                                   SkShader::kRepeat_TileMode);
+        fPaint.setShader(s)->unref();
+    }
+
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
         SkPaint paint(fPaint);
         this->setupPaint(&paint);