Reland "[CFI] Enable type generalization for LCMS"

This relands commit 7829b7048d5cf13a4f1a806fed57f2440d1b5dec.

This uses a new version of clang with a fix for the LSan issue that
caused the previous revert.

Original change's description:
> [CFI] Enable type generalization for LCMS
>
> Control Flow Integrity [1] indirect call checking verifies that function
> pointers only call valid functions with a matching type signature. This
> condition can be too strict, a common form of 'abstraction' relies on
> function pointers being cast to generalize argument pointer types to
> void*.
>
> In LCMS these failures occur because of casts of function pointers called
> as both _cmsInterpFn16 (cmsInterpFunction.Lerp16) and _cmsOPTeval16Fn (as
> an argument to _cmsPipelineSetOptimizationParameters) types making it
> difficult to refactor out easily. Instead, enabling the type
> generalization build config weakens the type checking performed for
> CFI-icall to accomodate this common type of casts.
>
> [1] https://www.chromium.org/developers/testing/control-flow-integrity
>
> Bug: 785442
> Change-Id: Ib42fb1b4e152d5042b170698c2707ebb9e0cc1ee
> Reviewed-on: https://pdfium-review.googlesource.com/19250
> Commit-Queue: dsinclair <dsinclair@chromium.org>
> Reviewed-by: dsinclair <dsinclair@chromium.org>

Bug: 785442
Change-Id: Ice696e4f496fa380f8af053577bde7e46c049590
Reviewed-on: https://pdfium-review.googlesource.com/22265
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
diff --git a/DEPS b/DEPS
index 8c267ac..2f704df 100644
--- a/DEPS
+++ b/DEPS
@@ -18,7 +18,7 @@
   'build_revision': '097c79babc9b2ce40b61c3e33da1c6681acf837c',
   'buildtools_revision': 'b36c7b60ed73919b157c7d23ec5fce2aa69ab05e',
   'catapult_revision': 'd624b3ced2c81d4fb4ea98a8dbb4532272cc1e0a',
-  'clang_revision': '8427dae2b5a769314af722e09000563b5184ba06',
+  'clang_revision': 'ac1e5f78c39dc2a262af149404dd36c140eecdc1',
   'cygwin_revision': 'c89e446b273697fadf3a10ff1007a97c0b7de6df',
   'depot_tools_revision': '2e8d8348b8574f06c26dbf3ef959b5df11ba5148',
   'freetype_revision': '2c048a8a622e9f44f255aa3316026f124ac9ecbc',