SurfaceRange: Add convenience methods for debugging

Add some methods to allow printing out SurfaceRanges.

Bug: none
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel
Change-Id: I363a64ae45961897f031c7dc0379d21462af29a5
Reviewed-on: https://chromium-review.googlesource.com/1142512Reviewed-by: Saman Sami <samans@chromium.org>
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576353}

components/viz/common/surfaces/surface_range.cc

@@ -4,6 +4,8 @@
 
 #include "components/viz/common/surfaces/surface_range.h"
 
+#include "base/strings/stringprintf.h"
+
 namespace viz {
 
 SurfaceRange::SurfaceRange() = default;
@@ -45,4 +47,14 @@ bool SurfaceRange::IsValid() const {
   return end_.local_surface_id().IsSameOrNewerThan(start_->local_surface_id());
 }
 
+std::string SurfaceRange::ToString() const {
+  return base::StringPrintf("SurfaceRange(start: %s, end: %s)",
+                            start_ ? start_->ToString().c_str() : "none",
+                            end_.ToString().c_str());
+}
+
+std::ostream& operator<<(std::ostream& out, const SurfaceRange& surface_range) {
+  return out << surface_range.ToString();
+}
+
 }  // namespace viz

components/viz/common/surfaces/surface_range.h

@@ -41,6 +41,8 @@ class VIZ_COMMON_EXPORT SurfaceRange {
 
   const SurfaceId& end() const { return end_; }
 
+  std::string ToString() const;
+
  private:
   friend struct mojo::StructTraits<mojom::SurfaceRangeDataView, SurfaceRange>;
 
@@ -48,6 +50,9 @@ class VIZ_COMMON_EXPORT SurfaceRange {
   SurfaceId end_;
 };
 
+VIZ_COMMON_EXPORT std::ostream& operator<<(std::ostream& out,
+                                           const SurfaceRange& surface_range);
+
 }  // namespace viz
 
 #endif  // COMPONENTS_VIZ_COMMON_SURFACES_SURFACE_RANGE_H_