skia: Crash when a discardable allocation fails.

A recent change (see crbug.com/983348) made the allocation of discardable memory
return nullptr in some cases, instead of crashing. Skia is not expecting this,
triggering a nullptr dereference.

This goes back to the previous behavior (crash in case of allocation failure),
while the proper fix is to make skia expect a nullptr return value. As a
consequence, this fix is temporary until upstream skia is updated.

Bug: 1034271, 983348
Change-Id: Idc3937898e897a19ca4e6793ab4e79626fe1b319
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1968985
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Benoit L <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#725462}

skia/ext/SkDiscardableMemory_chrome.cc

@@ -8,6 +8,7 @@
 
 #include <utility>
 
+#include "base/bind_helpers.h"
 #include "base/memory/discardable_memory.h"
 #include "base/memory/discardable_memory_allocator.h"
 
@@ -37,7 +38,10 @@ SkDiscardableMemoryChrome::CreateMemoryAllocatorDump(
 }
 
 SkDiscardableMemory* SkDiscardableMemory::Create(size_t bytes) {
-  return new SkDiscardableMemoryChrome(
-      base::DiscardableMemoryAllocator::GetInstance()
-          ->AllocateLockedDiscardableMemory(bytes));
+  // TODO(crbug.com/1034271): Make the caller handle a nullptr return value,
+  // and do not die when the allocation fails.
+  auto discardable = base::DiscardableMemoryAllocator::GetInstance()
+                         ->AllocateLockedDiscardableMemoryWithRetryOrDie(
+                             bytes, base::DoNothing());
+  return new SkDiscardableMemoryChrome(std::move(discardable));
 }