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/Image_039.cpp b/docs/examples/Image_039.cpp
new file mode 100644
index 0000000..e8e9414
--- /dev/null
+++ b/docs/examples/Image_039.cpp
@@ -0,0 +1,27 @@
+// 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=85a76163138a2720ac003691d6363938
+REG_FIDDLE(Image_039, 256, 256, false, 5) {
+void draw(SkCanvas* canvas) {
+    sk_sp<SkImageFilter> shadowFilter = SkDropShadowImageFilter::Make(
+                -10.0f * frame, 5.0f * frame, 3.0f, 3.0f, SK_ColorBLUE,
+                SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode,
+                nullptr);
+    sk_sp<SkImageFilter> offsetFilter = SkOffsetImageFilter::Make(40, 40, shadowFilter, nullptr);
+    SkIRect subset = image->bounds();
+    SkIRect clipBounds = image->bounds();
+    clipBounds.outset(60, 60);
+    SkIRect outSubset;
+    SkIPoint offset;
+    sk_sp<SkImage> filtered(image->makeWithFilter(offsetFilter.get(), subset, clipBounds,
+                            &outSubset, &offset));
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setStyle(SkPaint::kStroke_Style);
+    canvas->drawLine(0, 0, offset.fX, offset.fY, paint);
+    canvas->translate(offset.fX, offset.fY);
+    canvas->drawImage(filtered, 0, 0);
+    canvas->drawRect(SkRect::Make(outSubset), paint);
+}
+}  // END FIDDLE