Fix up all the easy virtual ... SK_OVERRIDE cases.

This fixes every case where virtual and SK_OVERRIDE were on the same line,
which should be the bulk of cases.  We'll have to manually clean up the rest
over time unless I level up in regexes.

for f in (find . -type f); perl -p -i -e 's/virtual (.*)SK_OVERRIDE/\1SK_OVERRIDE/g' $f; end

BUG=skia:

Review URL: https://codereview.chromium.org/806653007
diff --git a/gm/gradient_matrix.cpp b/gm/gradient_matrix.cpp
index 275acc8..94f40cb 100644
--- a/gm/gradient_matrix.cpp
+++ b/gm/gradient_matrix.cpp
@@ -120,7 +120,7 @@
     }
 
 protected:
-    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+    uint32_t onGetFlags() const SK_OVERRIDE {
         return kSkipTiled_Flag;
     }
 
@@ -128,11 +128,11 @@
         return SkString("gradient_matrix");
     }
 
-    virtual SkISize onISize() SK_OVERRIDE {
+    SkISize onISize() SK_OVERRIDE {
         return SkISize::Make(800, 800);
     }
 
-    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+    void onDraw(SkCanvas* canvas) SK_OVERRIDE {
         draw_gradients(canvas, &make_linear_gradient,
                       linearPts, SK_ARRAY_COUNT(linearPts));