Don't call SetEmbeddedColorProfile if null profile

Don't call SetEmbeddedColorProfile() if profile is a null pointer.
SetEmbeddedColorProfile() sets
source_to_target_color_transform_needs_update_ to true, which causes
extra work to be done when ColorTransform() is called later.

Change-Id: I63f1097547f168ce4522240c265de1caa8e01de6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2213449Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Wan-Teh Chang <wtc@google.com>
Cr-Commit-Position: refs/heads/master@{#772432}

third_party/blink/renderer/platform/image-decoders/jpeg/jpeg_image_decoder.cc

@@ -719,7 +719,8 @@ class JPEGImageReader final {
                     profile = nullptr;
                   break;
               }
-              Decoder()->SetEmbeddedColorProfile(std::move(profile));
+              if (profile)
+                Decoder()->SetEmbeddedColorProfile(std::move(profile));
             } else {
               DLOG(ERROR) << "Failed to parse image ICC profile";
             }