Roll ICU 45a095d5..a05f412f

Picks up https://codereview.chromium.org/1171203002
to add |isReferenceCounted| to the converter data structure.

BUG=465175
TEST=see the bug
TBR=jyasskin@chromium.org

Review URL: https://codereview.chromium.org/1171283003

Cr-Commit-Position: refs/heads/master@{#333679}

DEPS

@@ -126,7 +126,7 @@ deps = {
    Var('chromium_git') + '/chromium/blink.git' + '@' +  Var('webkit_revision'),
 
   'src/third_party/icu':
-   Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '45a095d561334871dd8673cf8e5cca330d33f521',
+   Var('chromium_git') + '/chromium/deps/icu.git' + '@' + 'a05f412f70489b77da0ddeb8baa31c68e3eff2c6',
 
   'src/third_party/libexif/sources':
    Var('chromium_git') + '/chromium/deps/libexif/sources.git' + '@' + 'ed98343daabd7b4497f97fda972e132e6877c48a',