Compile all fiddle examples locally

Motivation: it would be a good idea if the API documentation examples
were checked into the skia repository, so we could make sure they
compile as part of the commit queue.

Fiddle would make/update a named fiddle each time it gets a new
commit of Skia, extracted from the code in the examples/ directory.
The docs would point at those named fiddles.  Named fiddles have urls
in the form:

    https://fiddle.skia.org/c/@Bitmap_000

Then we would stick a link to the example into the header documentation
like this:

    /** Allocates the pixel memory for the bitmap, given its dimensions
        and SkColorType. Returns true on success, where success means
        either setPixels() or setPixelRef() was called.

        @param bitmap  SkBitmap containing SkImageInfo as input, and
                       SkPixelRef as output
        @return        true if SkPixelRef was allocated

        @example       https://fiddle.skia.org/c/@Bitmap_000
    */
    bool allocPixelRef(SkBitmap* bitmap) override;

There are still around 200 disabled examples that need to be fixed
(these result from API changes since the author left).

Change-Id: I14a31348a9ccaaa31f65424b91e3a3533d2583a7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/198824
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
diff --git a/docs/examples/Matrix_072.cpp b/docs/examples/Matrix_072.cpp
new file mode 100644
index 0000000..a878ce4
--- /dev/null
+++ b/docs/examples/Matrix_072.cpp
@@ -0,0 +1,34 @@
+#if 0  // Disabled until updated to use current API.
+// Copyright 2019 Google LLC.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+#include "fiddle/examples.h"
+// HASH=c851d1313e8909aaea4f0591699fdb7b
+REG_FIDDLE(Matrix_072, 256, 256, false, 0) {
+void draw(SkCanvas* canvas) {
+    const SkPoint src[] = { { 0, 0}, {30,   0}, {30, -30}, { 0, -30} };
+    const SkPoint dst[] = { {50, 0}, {80, -10}, {90, -30}, {60, -40} };
+    SkPaint blackPaint;
+    blackPaint.setAntiAlias(true);
+    blackPaint.setTextSize(42);
+    SkPaint redPaint = blackPaint;
+    redPaint.setColor(SK_ColorRED);
+    for (int count : { 1, 2, 3, 4 } ) {
+        canvas->translate(35, 55);
+        for (int index = 0; index < count; ++index) {
+            canvas->drawCircle(src[index], 3, blackPaint);
+            canvas->drawCircle(dst[index], 3, blackPaint);
+            if (index > 0) {
+                canvas->drawLine(src[index], src[index - 1], blackPaint);
+                canvas->drawLine(dst[index], dst[index - 1], blackPaint);
+            }
+        }
+        SkMatrix matrix;
+        matrix.setPolyToPoly(src, dst, count);
+        canvas->drawString("A", src[0].fX, src[0].fY, redPaint);
+        SkAutoCanvasRestore acr(canvas, true);
+        canvas->concat(matrix);
+        canvas->drawString("A", src[0].fX, src[0].fY, redPaint);
+    }
+}
+}  // END FIDDLE
+#endif  // Disabled until updated to use current API.