update_engine: Remove the duplicate BlocksInExtents

This patch removes the duplicate BlocksInExtents from extent_utils.h and fixes
the remainder of the code to reflect this change.

BUG=none
TEST=unittests pass;

Change-Id: I76f5106f75072b20cd8f41f081b2f2b07aeac9a8
Reviewed-on: https://chromium-review.googlesource.com/812009
Commit-Ready: Amin Hassani <ahassani@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Alex Deymo <deymo@google.com>
Reviewed-by: Sen Jiang <senj@chromium.org>
diff --git a/payload_consumer/extent_reader_unittest.cc b/payload_consumer/extent_reader_unittest.cc
index 9821775..b7059bc 100644
--- a/payload_consumer/extent_reader_unittest.cc
+++ b/payload_consumer/extent_reader_unittest.cc
@@ -81,7 +81,7 @@
   DirectExtentReader reader;
   EXPECT_TRUE(reader.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
   EXPECT_TRUE(reader.Seek(0));
-  brillo::Blob blob1(BlocksInExtents(extents) * kBlockSize);
+  brillo::Blob blob1(utils::BlocksInExtents(extents) * kBlockSize);
   EXPECT_TRUE(reader.Read(blob1.data(), blob1.size()));
   brillo::Blob blob2;
   ReadExtents(extents, &blob2);
@@ -112,7 +112,7 @@
   DirectExtentReader reader;
   EXPECT_TRUE(reader.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
   EXPECT_TRUE(reader.Seek(0));
-  brillo::Blob blob(BlocksInExtents(extents) * kBlockSize + 1);
+  brillo::Blob blob(utils::BlocksInExtents(extents) * kBlockSize + 1);
   EXPECT_FALSE(reader.Read(blob.data(), blob.size()));
 }
 
@@ -152,7 +152,7 @@
   brillo::Blob result;
   ReadExtents(extents, &result);
 
-  brillo::Blob blob(BlocksInExtents(extents) * kBlockSize);
+  brillo::Blob blob(utils::BlocksInExtents(extents) * kBlockSize);
   srand(time(nullptr));
   uint32_t rand_seed;
   for (size_t idx = 0; idx < kRandomIterations; idx++) {