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/Bitmap_052.cpp b/docs/examples/Bitmap_052.cpp
new file mode 100644
index 0000000..54e29cb
--- /dev/null
+++ b/docs/examples/Bitmap_052.cpp
@@ -0,0 +1,45 @@
+// 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=eb6f861ca1839146d26e40d56c2a001c
+REG_FIDDLE(Bitmap_052, 256, 100, false, 0) {
+class LargePixelRef : public SkPixelRef {
+public:
+    LargePixelRef(const SkImageInfo& info, char* storage, size_t rowBytes)
+        : SkPixelRef(info.width(), info.height(), storage, rowBytes) {
+    }
+    ~LargePixelRef() override {
+        delete[] (char* ) this->pixels();
+    }
+};
+class LargeAllocator : public SkBitmap::Allocator {
+public:
+    bool allocPixelRef(SkBitmap* bitmap) override {
+        const SkImageInfo& info = bitmap->info();
+        uint64_t rowBytes = info.minRowBytes64();
+        uint64_t size = info.height() * rowBytes;
+        char* addr = new char[size];
+        if (nullptr == addr) {
+            return false;
+        }
+        sk_sp<SkPixelRef> pr = sk_sp<SkPixelRef>(new LargePixelRef(info, addr, rowBytes));
+        if (!pr) {
+            return false;
+        }
+        bitmap->setPixelRef(std::move(pr), 0, 0);
+        return true;
+    }
+};
+
+void draw(SkCanvas* canvas) {
+   LargeAllocator largeAllocator;
+   SkBitmap bitmap;
+   int width = 100; // make this 20000
+   int height = 100; // and this 100000 to allocate 8 gigs on a 64-bit platform
+   bitmap.setInfo(SkImageInfo::MakeN32(width, height, kOpaque_SkAlphaType));
+   if (bitmap.tryAllocPixels(&largeAllocator)) {
+       bitmap.eraseColor(0xff55aa33);
+       canvas->drawBitmap(bitmap, 0, 0);
+   }
+}
+}  // END FIDDLE