Remove work from constructors to facilitate debugging.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1562093002

Review URL: https://codereview.chromium.org/1562093002

gm/blurroundrect.cpp

@@ -22,24 +22,9 @@
 // This GM mimics a blurred RR seen in the wild.
 class BlurRoundRectGM : public skiagm::GM {
 public:
-    BlurRoundRectGM(int width, int height, int radius)
-        : fName("blurroundrect")
-    {
-        SkRect r = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));
-        fRRect.setRectXY(r, SkIntToScalar(radius), SkIntToScalar(radius));
-        fName.appendf("-WH-%ix%i-corner-%i", width, height, radius);
-    }
-
     BlurRoundRectGM(int width, int height)
-        : fName("blurroundrect") {
+        : fName("blurroundrect"), fWidth(width), fHeight(height) {
         fName.appendf("-WH-%ix%i-unevenCorners", width,  height);
-        SkVector radii[4];
-        radii[0].set(SkIntToScalar(30), SkIntToScalar(30));
-        radii[1].set(SkIntToScalar(10), SkIntToScalar(10));
-        radii[2].set(SkIntToScalar(30), SkIntToScalar(30));
-        radii[3].set(SkIntToScalar(10), SkIntToScalar(10));
-        SkRect r = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));
-        fRRect.setRectRadii(r, radii);
     }
 
     SkString onShortName() override {
@@ -47,8 +32,17 @@ public:
     }
 
     SkISize onISize() override {
-        return SkISize::Make(SkScalarCeilToInt(fRRect.rect().width()),
-                             SkScalarCeilToInt(fRRect.rect().height()));
+        return SkISize::Make(fWidth, fHeight);
+    }
+
+    void onOnceBeforeDraw() override {
+        SkVector radii[4];
+        radii[0].set(SkIntToScalar(30), SkIntToScalar(30));
+        radii[1].set(SkIntToScalar(10), SkIntToScalar(10));
+        radii[2].set(SkIntToScalar(30), SkIntToScalar(30));
+        radii[3].set(SkIntToScalar(10), SkIntToScalar(10));
+        SkRect r = SkRect::MakeWH(SkIntToScalar(fWidth), SkIntToScalar(fHeight));
+        fRRect.setRectRadii(r, radii);
     }
 
     void onDraw(SkCanvas* canvas) override {
@@ -89,6 +83,7 @@ public:
 private:
     SkString        fName;
     SkRRect         fRRect;
+    int             fWidth, fHeight;
 
     typedef skiagm::GM INHERITED;
 };

gm/composeshader.cpp

@@ -162,13 +162,14 @@ static SkShader* make_linear_gradient_shader(int length) {
 
 class ComposeShaderBitmapGM : public skiagm::GM {
 public:
-    ComposeShaderBitmapGM()
-        : fColorBitmapShader(nullptr)
-        , fAlpha8BitmapShader(nullptr)
-        , fLinearGradientShader(nullptr)
-    {
+    ComposeShaderBitmapGM() {}
+    ~ComposeShaderBitmapGM() {
+        SkSafeUnref(fColorBitmapShader);
+        SkSafeUnref(fAlpha8BitmapShader);
+        SkSafeUnref(fLinearGradientShader);
     }
 
+protected:
     void onOnceBeforeDraw() override {
         draw_color_bm(&fColorBitmap, squareLength);
         draw_alpha8_bm(&fAlpha8Bitmap, squareLength);
@@ -181,13 +182,6 @@ public:
         fLinearGradientShader = make_linear_gradient_shader(squareLength);
     }
 
-    ~ComposeShaderBitmapGM() {
-        SkSafeUnref(fColorBitmapShader);
-        SkSafeUnref(fAlpha8BitmapShader);
-        SkSafeUnref(fLinearGradientShader);
-    }
-
-protected:
     SkString onShortName() override {
         return SkString("composeshader_bitmap");
     }
@@ -230,6 +224,7 @@ protected:
             canvas->translate(0, r.height() + 5);
         }
     }
+    
 private:
     /** This determines the length and width of the bitmaps used in the SkComposeShaders.  Values
      *  above 20 may cause an SkASSERT to fail in SkSmallAllocator. However, larger values will
@@ -240,9 +235,9 @@ private:
 
     SkBitmap fColorBitmap;
     SkBitmap fAlpha8Bitmap;
-    SkShader* fColorBitmapShader;
-    SkShader* fAlpha8BitmapShader;
-    SkShader* fLinearGradientShader;
+    SkShader* fColorBitmapShader{nullptr};
+    SkShader* fAlpha8BitmapShader{nullptr};
+    SkShader* fLinearGradientShader{nullptr};
 
     typedef GM INHERITED;
 };

gm/rrects.cpp

@@ -26,12 +26,15 @@ public:
         kAA_Clip_Type,
         kEffect_Type,
     };
-    RRectGM(Type type) : fType(type) {
+    RRectGM(Type type) : fType(type) { }
+
+protected:
+
+    void onOnceBeforeDraw() override {
         this->setBGColor(sk_tool_utils::color_to_565(0xFFDDDDDD));
         this->setUpRRects();
     }
 
-protected:
     SkString onShortName() override {
         SkString name("rrect");
         switch (fType) {