Add Histogram Macros to Skia

Adds a set of histogram macros to Skia, modeled after Chrome's
UMA_HISTOGRAM_* macros. These allow logging of high frequency events,
and are useful to analyze real world usage of certain features.

By default, these macros are no-ops. Users can provide a custom
header file which defines these macros if they wish to collect
histogram data. Chrome will provide such a header.

I've currently only added two macros:
- SK_HISTOGRAM_BOOLEAN - logs a true/false type relationship (whether
we are tiling a texture or not on each draw).
- SK_HISTOGRAM_ENUMERATION - logs a set of potential values (which of
a number of choices were selected for the texture upload path).

We could add more unused macros at the moment, but it seems easier to
add these as needed, WDYT?

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1652053004

Review URL: https://codereview.chromium.org/1652053004

2 files changed, 7 insertions, 0 deletions

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index c0a05797ea..060b2a1e45 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -925,6 +925,10 @@ void SkGpuDevice::drawTiledBitmap(const SkBitmap& bitmap,
                                   int tileSize,
                                   bool bicubic) {
     ASSERT_SINGLE_OWNER
+
+    // This is the funnel for all paths that draw tiled bitmaps/images. Log histogram entry.
+    SK_HISTOGRAM_BOOLEAN("DrawTiled", true);
+
     // The following pixel lock is technically redundant, but it is desirable
     // to lock outside of the tile loop to prevent redecoding the whole image
     // at each tile in cases where 'bitmap' holds an SkDiscardablePixelRef that
diff --git a/src/gpu/SkGpuDevice_drawTexture.cpp b/src/gpu/SkGpuDevice_drawTexture.cpp
index efbc6c98d5..5c5fb12421 100644
--- a/src/gpu/SkGpuDevice_drawTexture.cpp
+++ b/src/gpu/SkGpuDevice_drawTexture.cpp
@@ -94,6 +94,9 @@ void SkGpuDevice::drawTextureProducer(GrTextureProducer* producer,
                                       const SkMatrix& viewMatrix,
                                       const GrClip& clip,
                                       const SkPaint& paint) {
+    // This is the funnel for all non-tiled bitmap/image draw calls. Log a histogram entry.
+    SK_HISTOGRAM_BOOLEAN("DrawTiled", false);
+
     // Figure out the actual dst and src rect by clipping the src rect to the bounds of the
     // adjuster. If the src rect is clipped then the dst rect must be recomputed. Also determine
     // the matrix that maps the src rect to the dst rect.