Add third_party/fast_float dependency

Starting with https://crrev.com/c/5790306, V8 requires the fast_float
library to do string to double conversions. Add this dependency for
PDFium as well.

Change-Id: I3a8c7fd01ccff86ba4f23084c53be76259a4b4c3
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/123994
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@google.com>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

.gitignore

diff --git a/.gitignore b/.gitignore
index aa70d5c..1ffe3ee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@
 /third_party/clang-format
 /third_party/cpu_features/src
 /third_party/depot_tools
+/third_party/fast_float/src
 /third_party/fp16/src
 /third_party/freetype/src
 /third_party/googletest/src

DEPS

diff --git a/DEPS b/DEPS
index 4867ded..9746dd3 100644
--- a/DEPS
+++ b/DEPS
@@ -102,6 +102,10 @@
   # and whatever else without interference from each other.
   'depot_tools_revision': 'caa77da9568fb7c48c9db679cf9dc0ae20080585',
   # Three lines of non-changing comments so that
+  # the commit queue can handle CLs rolling fast_float
+  # and whatever else without interference from each other.
+  'fast_float_revision': '3e57d8dcfb0a04b5a8a26b486b54490a2e9b310f',
+  # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling fp16
   # and whatever else without interference from each other.
   'fp16_revision': '581ac1c79dd9d9f6f4e8b2934e7a55c7becf0799',
@@ -328,6 +332,10 @@
     Var('chromium_git') + '/chromium/tools/depot_tools.git@' +
         Var('depot_tools_revision'),
 
+  'third_party/fast_float/src':
+    Var('chromium_git') + '/external/github.com/fastfloat/fast_float.git@' +
+        Var('fast_float_revision'),
+
   'third_party/fp16/src':
     Var('chromium_git') + '/external/github.com/Maratyszcza/FP16.git@' +
         Var('fp16_revision'),

third_party/fast_float/BUILD.gn

diff --git a/third_party/fast_float/BUILD.gn b/third_party/fast_float/BUILD.gn
new file mode 100644
index 0000000..5ee373d
--- /dev/null
+++ b/third_party/fast_float/BUILD.gn
@@ -0,0 +1,18 @@
+# Copyright 2024 The PDFium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/gclient_args.gni")
+
+config("fast_float_config") {
+  include_dirs = [ "src/include" ]
+}
+
+source_set("fast_float") {
+  public = [ "src/include/fast_float/fast_float.h" ]
+
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+
+  public_configs = [ ":fast_float_config" ]
+}

third_party/fast_float/README.pdfium

diff --git a/third_party/fast_float/README.pdfium b/third_party/fast_float/README.pdfium
new file mode 100644
index 0000000..4b58ec0
--- /dev/null
+++ b/third_party/fast_float/README.pdfium
@@ -0,0 +1,15 @@
+Name: fast_float
+URL: https://github.com/fastfloat/fast_float
+Version: 6.1.4
+Revision: d7417618f93d2c47e9bbde561510f9fc8bafe003
+License: MIT
+License File: src/LICENSE-MIT
+Shipped: yes
+Security Critical: yes
+CPEPrefix: unknown
+
+Description:
+Fast, header-only implementation of char* to float/double conversions.
+
+Local Modifications:
+None