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/Canvas_031.cpp b/docs/examples/Canvas_031.cpp
new file mode 100644
index 0000000..33d6e55
--- /dev/null
+++ b/docs/examples/Canvas_031.cpp
@@ -0,0 +1,28 @@
+#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=8460bf8b013f46c67e0bd96e13451aff
+REG_FIDDLE(Canvas_031, 256, 256, false, 0) {
+void draw(SkCanvas* canvas) {
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setLCDRenderText(true);
+    paint.setTextSize(20);
+    for (auto preserve : { false, true } ) {
+        preserve ? canvas->saveLayerPreserveLCDTextRequests(nullptr, nullptr)
+                 : canvas->saveLayer(nullptr, nullptr);
+        SkPaint p;
+        p.setColor(SK_ColorWHITE);
+        // Comment out the next line to draw on a non-opaque background.
+        canvas->drawRect(SkRect::MakeLTRB(25, 40, 200, 70), p);
+        canvas->drawString("Hamburgefons", 30, 60, paint);
+        p.setColor(0xFFCCCCCC);
+        canvas->drawRect(SkRect::MakeLTRB(25, 70, 200, 100), p);
+        canvas->drawString("Hamburgefons", 30, 90, paint);
+        canvas->restore();
+        canvas->translate(0, 80);
+    }
+}
+}  // END FIDDLE
+#endif  // Disabled until updated to use current API.