Add option for SKP capture without reencoding images

Generating SKPs with this new flag will allow us to obtain a
large set of images that is representative of what is common
on the web.

BUG=

Review URL: https://codereview.chromium.org/1710553002

Cr-Commit-Position: refs/heads/master@{#377026}

3 files changed, 51 insertions, 9 deletions

diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index f4749f7..70363f3 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -801,6 +801,12 @@ const char kSitePerProcess[]                = "site-per-process";
 // TODO(gab): Get rid of this switch entirely.
 const char kSkipGpuDataLoading[]            = "skip-gpu-data-loading";
 
+// Skips reencoding bitmaps as PNGs when the encoded data is unavailable
+// during SKP capture.  This allows for obtaining an accurate sample of
+// the types of images on the web, rather than being weighted towards PNGs
+// that we have encoded ourselves.
+const char kSkipReencodingOnSKPCapture[]    = "skip-reencoding-on-skp-capture";
+
 // Specifies if the browser should start in fullscreen mode, like if the user
 // had pressed F11 right after startup.
 const char kStartFullscreen[] = "start-fullscreen";
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index e9b4619..fe08255 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -224,6 +224,7 @@ extern const char kShowPaintRects[];
 CONTENT_EXPORT extern const char kSingleProcess[];
 CONTENT_EXPORT extern const char kSitePerProcess[];
 CONTENT_EXPORT extern const char kSkipGpuDataLoading[];
+extern const char kSkipReencodingOnSKPCapture[];
 CONTENT_EXPORT extern const char kStartFullscreen[];
 CONTENT_EXPORT extern const char kStatsCollectionController[];
 CONTENT_EXPORT extern const char kTabCaptureDownscaleQuality[];
diff --git a/content/renderer/gpu/gpu_benchmarking_extension.cc b/content/renderer/gpu/gpu_benchmarking_extension.cc
index 8a807ff..f471360 100644
--- a/content/renderer/gpu/gpu_benchmarking_extension.cc
+++ b/content/renderer/gpu/gpu_benchmarking_extension.cc
@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "base/base64.h"
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
@@ -21,6 +22,7 @@
 #include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
 #include "content/common/input/synthetic_tap_gesture_params.h"
 #include "content/public/child/v8_value_converter.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/renderer/chrome_object_extensions_utils.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/renderer/gpu/render_widget_compositor.h"
@@ -54,19 +56,52 @@ namespace content {
 
 namespace {
 
-class PNGSerializer : public SkPixelSerializer {
+class EncodingSerializer : public SkPixelSerializer {
  protected:
   bool onUseEncodedData(const void* data, size_t len) override { return true; }
 
   SkData* onEncode(const SkPixmap& pixmap) override {
-    SkBitmap bm;
-    // The const_cast is fine, since we only read from the bitmap.
-    if (bm.installPixels(pixmap.info(),
-                         const_cast<void*>(pixmap.addr()),
-                         pixmap.rowBytes())) {
-      std::vector<unsigned char> vector;
-      if (gfx::PNGCodec::EncodeBGRASkBitmap(bm, false, &vector)) {
+    std::vector<uint8_t> vector;
+
+    const base::CommandLine& commandLine =
+        *base::CommandLine::ForCurrentProcess();
+    if (commandLine.HasSwitch(switches::kSkipReencodingOnSKPCapture)) {
+        // In this case, we just want to store some useful information
+        // about the image to replace the missing encoded data.
+
+        // First make sure that the data does not accidentally match any
+        // image signatures.
+        vector.push_back(0xFF);
+        vector.push_back(0xFF);
+        vector.push_back(0xFF);
+        vector.push_back(0xFF);
+
+        // Save the width and height.
+        uint32_t width = pixmap.width();
+        uint32_t height = pixmap.height();
+        vector.push_back(width & 0xFF);
+        vector.push_back((width >> 8) & 0xFF);
+        vector.push_back((width >> 16) & 0xFF);
+        vector.push_back((width >> 24) & 0xFF);
+        vector.push_back(height & 0xFF);
+        vector.push_back((height >> 8) & 0xFF);
+        vector.push_back((height >> 16) & 0xFF);
+        vector.push_back((height >> 24) & 0xFF);
+
+        // Save any additional information about the bitmap that may be
+        // interesting.
+        vector.push_back(pixmap.colorType());
+        vector.push_back(pixmap.alphaType());
         return SkData::NewWithCopy(&vector.front(), vector.size());
+    } else {
+      SkBitmap bm;
+      // The const_cast is fine, since we only read from the bitmap.
+      if (bm.installPixels(pixmap.info(),
+                           const_cast<void*>(pixmap.addr()),
+                           pixmap.rowBytes())) {
+        if (gfx::PNGCodec::EncodeBGRASkBitmap(bm, false, &vector)) {
+          return SkData::NewWithCopy(&vector.front(), vector.size());
+        }
       }
     }
     return nullptr;
@@ -106,7 +141,7 @@ class SkPictureSerializer {
     SkFILEWStream file(filepath.c_str());
     DCHECK(file.isValid());
 
-    PNGSerializer serializer;
+    EncodingSerializer serializer;
     picture->serialize(&file, &serializer);
     file.fsync();
   }