Update to Chromium version 82.0.4085.0 (#749737)

- Building on macOS now requires the 10.15 SDK. Xcode 11.3 is recommended as
  Xcode 11.4 is not currently supported (see https://crbug.com/1065146).
- Jumbo build configuration is no longer supported.

Chromium is skipping the M82 release and consequently no CEF 4085 branch will
be created. For details on the Chromium decision see
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/Vn7uzglqLz0/JItlSrZxBAAJ

libcef/browser/chrome_profile_stub.h

@@ -22,6 +22,7 @@ class ChromeProfileStub : public Profile {
   // Profile methods.
   bool IsOffTheRecord() override;
   bool IsOffTheRecord() const override;
+  variations::VariationsClient* GetVariationsClient() override;
   scoped_refptr<base::SequencedTaskRunner> GetIOTaskRunner() override;
   std::string GetProfileUserName() const override;
   ProfileType GetProfileType() const override;
@@ -48,6 +49,8 @@ class ChromeProfileStub : public Profile {
   void SetCreationTimeForTesting(base::Time creation_time) override;
 
  private:
+  std::unique_ptr<variations::VariationsClient> variations_client_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeProfileStub);
 };