color: Clarify default behaviors

ui/gfx/icc_profile.h

Index: ui/gfx/icc_profile.h
diff --git a/ui/gfx/icc_profile.h b/ui/gfx/icc_profile.h
index cdbbf59085a9310b6229069d005eabc5c106ff24..18b80442ab2b46083f6fe231c339a45128a227de 100644
--- a/ui/gfx/icc_profile.h
+++ b/ui/gfx/icc_profile.h
@@ -77,6 +77,12 @@ class GFX_EXPORT ICCProfile {
   static const uint64_t test_id_generic_rgb_;
   static const uint64_t test_id_srgb_;
 
+  // Populate |icc_profile| with the ICCProfile corresponding to id |id|. Return
+  // false if |id| is not in the cache. If |only_if_needed| is true, then return
+  // false if |color_space_is_accurate_| is true for this profile (that is, if
+  // the ICCProfile is needed to know the space precisely).
+  static bool FromId(uint64_t id, bool only_if_needed, ICCProfile* icc_profile);
+
   // This method is used to hard-code the |id_| to a specific value, and is
   // used by test methods to ensure that they don't conflict with the values
   // generated in the browser.
@@ -94,11 +100,15 @@ class GFX_EXPORT ICCProfile {
   std::vector<char> data_;
 
   gfx::ColorSpace color_space_;
+  // True if |color_space_| accurately represents this color space (this is
+  // false e.g, for lookup-based profiles).
+  bool color_space_is_accurate_ = false;
 
   FRIEND_TEST_ALL_PREFIXES(SimpleColorSpace, BT709toSRGBICC);
   FRIEND_TEST_ALL_PREFIXES(SimpleColorSpace, GetColorSpace);
   friend int ::LLVMFuzzerTestOneInput(const uint8_t*, size_t);
   friend class ColorSpace;
+  friend class ColorTransformInternal;
   friend struct IPC::ParamTraits<gfx::ICCProfile>;
 };