crostini: Fix a disk resizing bug

Now that we round sizes to human-friendly numbers (e.g. nearest 0.1GiB),
and we round down the top of the range of allowed sizes, it's possible
to end up with a disk that's allocated a legal amount, but which is
beyond the slider range. Now we ensure that we always include whatever
size disk the user currently has in the range.

Bug: chromium:1126705
Test: Run new unit test that hits this case.

Change-Id: I7f8fb7bfe652b596da0763693699d74c6c61d39d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2459133
Commit-Queue: David Munro <davidmunro@google.com>
Auto-Submit: David Munro <davidmunro@google.com>
Reviewed-by: Fergus Dall <sidereal@google.com>
Cr-Commit-Position: refs/heads/master@{#815466}

chrome/browser/chromeos/crostini/crostini_disk.cc

@@ -151,6 +151,8 @@ void OnListVmDisks(
   VLOG(1) << "image_type: " << image->image_type();
   VLOG(1) << "size: " << image->size();
   VLOG(1) << "user_chosen_size: " << image->user_chosen_size();
+  VLOG(1) << "free_space: " << free_space;
+  VLOG(1) << "min_size: " << image->min_size();
 
   if (image->image_type() !=
       vm_tools::concierge::DiskImageType::DISK_IMAGE_RAW) {
@@ -207,17 +209,15 @@ std::vector<crostini::mojom::DiskSliderTickPtr> GetTicks(
     return {};
   }
   std::vector<int64_t> values = GetTicksForDiskSize(min, max);
+  DCHECK(!values.empty());
 
   // If the current size isn't on one of the ticks insert an extra tick for it.
+  // It's possible for the current size to be greater than the maximum tick,
+  // in which case we go up to whatever that size is.
   auto it = std::lower_bound(begin(values), end(values), current);
-  if (it != end(values)) {
-    if (*it != current) {
-      values.insert(it, current);
-    }
-    *out_default_index = std::distance(begin(values), it);
-  } else {
-    DCHECK(values.empty());
-    return {};
+  *out_default_index = std::distance(begin(values), it);
+  if (it == end(values) || *it != current) {
+    values.insert(it, current);
   }
 
   std::vector<crostini::mojom::DiskSliderTickPtr> ticks;

chrome/browser/chromeos/crostini/crostini_disk_unittest.cc

@@ -190,6 +190,24 @@ TEST_F(CrostiniDiskTest, DefaultIsCurrentValue) {
   EXPECT_GT(disk_info->ticks.at(disk_info->default_index + 1)->value, 3 * kGiB);
 }
 
+// Numbers taken from crbug/1126705.
+TEST_F(CrostiniDiskTest, AllocatedAboveMax) {
+  vm_tools::concierge::ListVmDisksResponse response;
+  auto* image = response.add_images();
+  response.set_success(true);
+  image->set_name("vm_name");
+  image->set_image_type(vm_tools::concierge::DiskImageType::DISK_IMAGE_RAW);
+  image->set_min_size(3260022784);
+  image->set_size(459561652224);
+  auto disk_info = OnListVmDisksWithResult("vm_name", 1120739328, response);
+  ASSERT_TRUE(disk_info);
+
+  ASSERT_TRUE(disk_info->ticks.size() > 3);
+  EXPECT_EQ(disk_info->default_index, disk_info->ticks.size() - 1);
+  EXPECT_EQ(disk_info->ticks.at(disk_info->default_index)->value,
+            image->size());
+}
+
 TEST_F(CrostiniDiskTest, AmountOfFreeDiskSpaceFailureIsHandled) {
   std::unique_ptr<CrostiniDiskInfo> disk_info;
   auto store_info =
@@ -346,6 +364,7 @@ TEST_F(CrostiniDiskTest, GetTicksForDiskSizeSmallRangeNonZeroStart) {
     EXPECT_FLOAT_EQ(ticks[n], expected[n]);
   }
 }
+
 TEST_F(CrostiniDiskTest, GetTicksForDiskSizeLargeRange) {
   // 5 ticks for 7 GiB, largest interval is 1GiB so we should end up with 8
   // 0.1 GiB ticks. For bonus coverage, start at non-zero non-round.